61855772400 has 180 divisors, whose sum is σ = 214867107000. Its totient is φ = 16478707200.

The previous prime is 61855772393. The next prime is 61855772483. The reversal of 61855772400 is 427755816.

61855772400 is a `hidden beast` number, since 618 + 5 + 5 + 7 + 7 + 24 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (180).

It is a super-2 number, since 2×61855772400² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3919726 + ... + 3935474.

It is an arithmetic number, because the mean of its divisors is an integer number (1193706150).

Almost surely, 2^61855772400 is an apocalyptic number.

61855772400 is a gapful number since it is divisible by the number (60) 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 61855772400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107433553500).

61855772400 is an abundant number, since it is smaller than the sum of its proper divisors (153011334600).

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

61855772400 is a wasteful number, since it uses less digits than its factorization.

61855772400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16864 (or 16850 counting only the distinct ones).

The product of its (nonzero) digits is 470400, while the sum is 45.

The spelling of 61855772400 in words is "sixty-one billion, eight hundred fifty-five million, seven hundred seventy-two thousand, four hundred".