21265020425 has 24 divisors (see below), whose sum is σ = 29253350880. Its totient is φ = 15203331200.

The previous prime is 21265020409. The next prime is 21265020449. The reversal of 21265020425 is 52402056212.

It is not a de Polignac number, because 21265020425 - 2⁴ = 21265020409 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 639092 + ... + 671541.

It is an arithmetic number, because the mean of its divisors is an integer number (1218889620).

Almost surely, 2^21265020425 is an apocalyptic number.

21265020425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21265020425 is a deficient number, since it is larger than the sum of its proper divisors (7988330455).

21265020425 is a wasteful number, since it uses less digits than its factorization.

21265020425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1310713 (or 1310708 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 29.

Adding to 21265020425 its reverse (52402056212), we get a palindrome (73667076637).

The spelling of 21265020425 in words is "twenty-one billion, two hundred sixty-five million, twenty thousand, four hundred twenty-five".