21515451425355 has 32 divisors (see below), whose sum is σ = 34457347284480. Its totient is φ = 11464037602560.

The previous prime is 21515451425309. The next prime is 21515451425371. The reversal of 21515451425355 is 55352415451512.

It is not a de Polignac number, because 21515451425355 - 2⁷ = 21515451425227 is a prime.

It is a super-2 number, since 2×21515451425355² (a number of 27 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 67219095 + ... + 67538415.

It is an arithmetic number, because the mean of its divisors is an integer number (1076792102640).

Almost surely, 2^{21515451425355} is an apocalyptic number.

21515451425355 is a deficient number, since it is larger than the sum of its proper divisors (12941895859125).

21515451425355 is a wasteful number, since it uses less digits than its factorization.

21515451425355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323571.

The product of its digits is 3000000, while the sum is 48.

Adding to 21515451425355 its reverse (55352415451512), we get a palindrome (76867866876867).

The spelling of 21515451425355 in words is "twenty-one trillion, five hundred fifteen billion, four hundred fifty-one million, four hundred twenty-five thousand, three hundred fifty-five".