21013131455 has 16 divisors (see below), whose sum is σ = 25478556480. Its totient is φ = 16635537408.

The previous prime is 21013131449. The next prime is 21013131473. The reversal of 21013131455 is 55413131012.

It is a cyclic number.

It is not a de Polignac number, because 21013131455 - 2¹⁰ = 21013130431 is a prime.

It is a super-2 number, since 2×21013131455² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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, 755231 + ... + 782559.

It is an arithmetic number, because the mean of its divisors is an integer number (1592409780).

Almost surely, 2^21013131455 is an apocalyptic number.

21013131455 is a deficient number, since it is larger than the sum of its proper divisors (4465425025).

21013131455 is a wasteful number, since it uses less digits than its factorization.

21013131455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28930.

The product of its (nonzero) digits is 1800, while the sum is 26.

Adding to 21013131455 its reverse (55413131012), we get a palindrome (76426262467).

The spelling of 21013131455 in words is "twenty-one billion, thirteen million, one hundred thirty-one thousand, four hundred fifty-five".