21400555451 has 32 divisors (see below), whose sum is σ = 25107703488. Its totient is φ = 18025021440.

The previous prime is 21400555441. The next prime is 21400555457. The reversal of 21400555451 is 15455500412.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21400555451 is a prime.

It is a super-2 number, since 2×21400555451² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21400555457) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3497771 + ... + 3503883.

It is an arithmetic number, because the mean of its divisors is an integer number (784615734).

Almost surely, 2^21400555451 is an apocalyptic number.

21400555451 is a deficient number, since it is larger than the sum of its proper divisors (3707148037).

21400555451 is a wasteful number, since it uses less digits than its factorization.

21400555451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6431.

The product of its (nonzero) digits is 20000, while the sum is 32.

The spelling of 21400555451 in words is "twenty-one billion, four hundred million, five hundred fifty-five thousand, four hundred fifty-one".