21250772500 has 30 divisors (see below), whose sum is σ = 46471194770. Its totient is φ = 8500308000.

The previous prime is 21250772489. The next prime is 21250772507. The reversal of 21250772500 is 527705212.

It can be written as a sum of positive squares in 5 ways, for example, as 2873174404 + 18377598096 = 53602^2 + 135564^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21250772507) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 4247655 + ... + 4252654.

Almost surely, 2^21250772500 is an apocalyptic number.

21250772500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21250772500 is an abundant number, since it is smaller than the sum of its proper divisors (25220422270).

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

21250772500 is an equidigital number, since it uses as much as digits as its factorization.

21250772500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8500333 (or 8500316 counting only the distinct ones).

The product of its (nonzero) digits is 9800, while the sum is 31.

The spelling of 21250772500 in words is "twenty-one billion, two hundred fifty million, seven hundred seventy-two thousand, five hundred".