21531747250 has 32 divisors (see below), whose sum is σ = 43408009008. Its totient is φ = 7950182400.

The previous prime is 21531747191. The next prime is 21531747253. The reversal of 21531747250 is 5274713512.

It can be written as a sum of positive squares in 8 ways, for example, as 81 + 21531747169 = 9^2 + 146737^2 .

It is a super-2 number, since 2×21531747250² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21531747253) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3309327 + ... + 3315826.

Almost surely, 2^21531747250 is an apocalyptic number.

21531747250 is an abundant number, since it is smaller than the sum of its proper divisors (21876261758).

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

21531747250 is a wasteful number, since it uses less digits than its factorization.

21531747250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6625183 (or 6625173 counting only the distinct ones).

The product of its (nonzero) digits is 58800, while the sum is 37.

The spelling of 21531747250 in words is "twenty-one billion, five hundred thirty-one million, seven hundred forty-seven thousand, two hundred fifty".