1661687215200 has 216 divisors, whose sum is σ = 5892263886600. Its totient is φ = 440640737280.

The previous prime is 1661687215187. The next prime is 1661687215213. The reversal of 1661687215200 is 25127861661.

1661687215200 is a `hidden beast` number, since 1 + 6 + 61 + 68 + 7 + 2 + 1 + 520 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (1661687215187) and next prime (1661687215213).

It is a super-2 number, since 2×1661687215200² (a number of 25 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 polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 644136 + ... + 1933464.

It is an arithmetic number, because the mean of its divisors is an integer number (27278999475).

Almost surely, 2^{1661687215200} is an apocalyptic number.

1661687215200 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 1661687215200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2946131943300).

1661687215200 is an abundant number, since it is smaller than the sum of its proper divisors (4230576671400).

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

1661687215200 is a wasteful number, since it uses less digits than its factorization.

1661687215200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1289534 (or 1289518 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The spelling of 1661687215200 in words is "one trillion, six hundred sixty-one billion, six hundred eighty-seven million, two hundred fifteen thousand, two hundred".