21255134131 has 16 divisors (see below), whose sum is σ = 26653102848. Its totient is φ = 16466695200.

The previous prime is 21255134107. The next prime is 21255134161. The reversal of 21255134131 is 13143155212.

It is a cyclic number.

It is not a de Polignac number, because 21255134131 - 2¹¹ = 21255132083 is a prime.

It is a super-2 number, since 2×21255134131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21255134131.

It is not an unprimeable number, because it can be changed into a prime (21255134101) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 784485 + ... + 811126.

It is an arithmetic number, because the mean of its divisors is an integer number (1665818928).

Almost surely, 2^21255134131 is an apocalyptic number.

21255134131 is a deficient number, since it is larger than the sum of its proper divisors (5397968717).

21255134131 is a wasteful number, since it uses less digits than its factorization.

21255134131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1595802.

The product of its digits is 3600, while the sum is 28.

Adding to 21255134131 its reverse (13143155212), we get a palindrome (34398289343).

The spelling of 21255134131 in words is "twenty-one billion, two hundred fifty-five million, one hundred thirty-four thousand, one hundred thirty-one".