21525530431 has 2 divisors, whose sum is σ = 21525530432. Its totient is φ = 21525530430.

The previous prime is 21525530387. The next prime is 21525530449. The reversal of 21525530431 is 13403552512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21525530431 - 2⁷ = 21525530303 is a prime.

It is a super-2 number, since 2×21525530431² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21525530393 and 21525530402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21525530491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10762765215 + 10762765216.

It is an arithmetic number, because the mean of its divisors is an integer number (10762765216).

Almost surely, 2^21525530431 is an apocalyptic number.

21525530431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21525530431 is an equidigital number, since it uses as much as digits as its factorization.

21525530431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18000, while the sum is 31.

The spelling of 21525530431 in words is "twenty-one billion, five hundred twenty-five million, five hundred thirty thousand, four hundred thirty-one".