2151561398400 has 1920 divisors, whose sum is σ = 9145718208000. Its totient is φ = 494478950400.

The previous prime is 2151561398351. The next prime is 2151561398407. The reversal of 2151561398400 is 48931651512.

It is a happy number.

2151561398400 is a `hidden beast` number, since 2 + 1 + 5 + 1 + 561 + 3 + 9 + 84 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1920).

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

It is not an unprimeable number, because it can be changed into a prime (2151561398407) by changing a digit.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 2595369186 + ... + 2595370014.

It is an arithmetic number, because the mean of its divisors is an integer number (4763394900).

Almost surely, 2^{2151561398400} is an apocalyptic number.

2151561398400 is a gapful number since it is divisible by the number (20) 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 2151561398400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4572859104000).

2151561398400 is an abundant number, since it is smaller than the sum of its proper divisors (6994156809600).

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

2151561398400 is a wasteful number, since it uses less digits than its factorization.

2151561398400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 932 (or 906 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The spelling of 2151561398400 in words is "two trillion, one hundred fifty-one billion, five hundred sixty-one million, three hundred ninety-eight thousand, four hundred".