1611261644400 has 240 divisors, whose sum is σ = 5740769829120. Its totient is φ = 429229843200.

The previous prime is 1611261644381. The next prime is 1611261644401. The reversal of 1611261644400 is 44461621161.

1611261644400 is a `hidden beast` number, since 1 + 6 + 1 + 1 + 2 + 6 + 1 + 644 + 4 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-3 number, since 3×1611261644400³ (a number of 38 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1611261644401) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 10540515 + ... + 10692285.

It is an arithmetic number, because the mean of its divisors is an integer number (23919874288).

Almost surely, 2^{1611261644400} is an apocalyptic number.

1611261644400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1611261644400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2870384914560).

1611261644400 is an abundant number, since it is smaller than the sum of its proper divisors (4129508184720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1611261644400 is a wasteful number, since it uses less digits than its factorization.

1611261644400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152781 (or 152764 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The spelling of 1611261644400 in words is "one trillion, six hundred eleven billion, two hundred sixty-one million, six hundred forty-four thousand, four hundred".