21631615247247 has 4 divisors (see below), whose sum is σ = 28842153663000. Its totient is φ = 14421076831496.

The previous prime is 21631615247239. The next prime is 21631615247261. The reversal of 21631615247247 is 74274251613612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21631615247247 - 2³ = 21631615247239 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21631615247247.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21631615247647) 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, 3605269207872 + ... + 3605269207877.

It is an arithmetic number, because the mean of its divisors is an integer number (7210538415750).

Almost surely, 2^{21631615247247} is an apocalyptic number.

21631615247247 is a deficient number, since it is larger than the sum of its proper divisors (7210538415753).

21631615247247 is an equidigital number, since it uses as much as digits as its factorization.

21631615247247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7210538415752.

The product of its digits is 3386880, while the sum is 51.

The spelling of 21631615247247 in words is "twenty-one trillion, six hundred thirty-one billion, six hundred fifteen million, two hundred forty-seven thousand, two hundred forty-seven".