21510453131 has 2 divisors, whose sum is σ = 21510453132. Its totient is φ = 21510453130.

The previous prime is 21510453121. The next prime is 21510453137. The reversal of 21510453131 is 13135401512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21510453131 - 2³⁴ = 4330583947 is a prime.

It is a super-2 number, since 2×21510453131² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21510453131.

It is not a weakly prime, because it can be changed into another prime (21510453137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10755226565 + 10755226566.

It is an arithmetic number, because the mean of its divisors is an integer number (10755226566).

Almost surely, 2^21510453131 is an apocalyptic number.

21510453131 is a deficient number, since it is larger than the sum of its proper divisors (1).

21510453131 is an equidigital number, since it uses as much as digits as its factorization.

21510453131 is an evil number, because the sum of its binary digits is even.

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

Adding to 21510453131 its reverse (13135401512), we get a palindrome (34645854643).

The spelling of 21510453131 in words is "twenty-one billion, five hundred ten million, four hundred fifty-three thousand, one hundred thirty-one".