21515453424355 has 16 divisors (see below), whose sum is σ = 29822489453664. Its totient is φ = 14727155284480.

The previous prime is 21515453424349. The next prime is 21515453424373. The reversal of 21515453424355 is 55342435451512.

It is not a de Polignac number, because 21515453424355 - 2⁹ = 21515453423843 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21515453424299 and 21515453424308.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11505589132 + ... + 11505591001.

It is an arithmetic number, because the mean of its divisors is an integer number (1863905590854).

Almost surely, 2^{21515453424355} is an apocalyptic number.

21515453424355 is a deficient number, since it is larger than the sum of its proper divisors (8307036029309).

21515453424355 is a wasteful number, since it uses less digits than its factorization.

21515453424355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23011180166.

The product of its digits is 7200000, while the sum is 49.

Adding to 21515453424355 its reverse (55342435451512), we get a palindrome (76857888875867).

The spelling of 21515453424355 in words is "twenty-one trillion, five hundred fifteen billion, four hundred fifty-three million, four hundred twenty-four thousand, three hundred fifty-five".