21497632308 has 90 divisors (see below), whose sum is σ = 59312901186. Its totient is φ = 6788689056.

The previous prime is 21497632307. The next prime is 21497632309. The reversal of 21497632308 is 80323679412.

21497632308 is a `hidden beast` number, since 2 + 1 + 4 + 9 + 7 + 632 + 3 + 0 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (21497632307) and next prime (21497632309).

It can be written as a sum of positive squares in only one way, i.e., 18157023504 + 3340608804 = 134748^2 + 57798^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21497632307) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 25066 + ... + 208862.

Almost surely, 2^21497632308 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21497632308, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29656450593).

21497632308 is an abundant number, since it is smaller than the sum of its proper divisors (37815268878).

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

21497632308 is a wasteful number, since it uses less digits than its factorization.

21497632308 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183851 (or 183821 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 45.

The spelling of 21497632308 in words is "twenty-one billion, four hundred ninety-seven million, six hundred thirty-two thousand, three hundred eight".