21947047508 has 12 divisors (see below), whose sum is σ = 39132000180. Its totient is φ = 10766476032.

The previous prime is 21947047501. The next prime is 21947047517. The reversal of 21947047508 is 80574074912.

It can be written as a sum of positive squares in 2 ways, for example, as 14713204804 + 7233842704 = 121298^2 + 85052^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21947047501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51761693 + ... + 51762116.

It is an arithmetic number, because the mean of its divisors is an integer number (3261000015).

Almost surely, 2^21947047508 is an apocalyptic number.

It is an amenable number.

21947047508 is a deficient number, since it is larger than the sum of its proper divisors (17184952672).

21947047508 is a wasteful number, since it uses less digits than its factorization.

21947047508 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103523866 (or 103523864 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 47.

The spelling of 21947047508 in words is "twenty-one billion, nine hundred forty-seven million, forty-seven thousand, five hundred eight".