21251253000 has 128 divisors (see below), whose sum is σ = 69793776000. Its totient is φ = 5368723200.

The previous prime is 21251252977. The next prime is 21251253007. The reversal of 21251253000 is 35215212.

It is not an unprimeable number, because it can be changed into a prime (21251253007) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 129415 + ... + 243414.

It is an arithmetic number, because the mean of its divisors is an integer number (545263875).

Almost surely, 2^21251253000 is an apocalyptic number.

21251253000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21251253000 is an abundant number, since it is smaller than the sum of its proper divisors (48542523000).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21251253000 is a wasteful number, since it uses less digits than its factorization.

21251253000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372872 (or 372858 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 21.

Adding to 21251253000 its reverse (35215212), we get a palindrome (21286468212).

The spelling of 21251253000 in words is "twenty-one billion, two hundred fifty-one million, two hundred fifty-three thousand".