15661161600 has 384 divisors, whose sum is σ = 62425468800. Its totient is φ = 3368878080.

The previous prime is 15661161599. The next prime is 15661161601. The reversal of 15661161600 is 616116651.

It is an interprime number because it is at equal distance from previous prime (15661161599) and next prime (15661161601).

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-2 number, since 2×15661161600² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15661161601) 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, 1135546 + ... + 1149254.

It is an arithmetic number, because the mean of its divisors is an integer number (162566325).

Almost surely, 2^15661161600 is an apocalyptic number.

15661161600 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 15661161600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31212734400).

15661161600 is an abundant number, since it is smaller than the sum of its proper divisors (46764307200).

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

15661161600 is a wasteful number, since it uses less digits than its factorization.

15661161600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13760 (or 13743 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 33.

The spelling of 15661161600 in words is "fifteen billion, six hundred sixty-one million, one hundred sixty-one thousand, six hundred".