21315231502 has 16 divisors (see below), whose sum is σ = 32156277552. Its totient is φ = 10596533760.

The previous prime is 21315231481. The next prime is 21315231523. The reversal of 21315231502 is 20513251312.

It is an interprime number because it is at equal distance from previous prime (21315231481) and next prime (21315231523).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 731068 + ... + 759664.

It is an arithmetic number, because the mean of its divisors is an integer number (2009767347).

Almost surely, 2^21315231502 is an apocalyptic number.

21315231502 is a deficient number, since it is larger than the sum of its proper divisors (10841046050).

21315231502 is a wasteful number, since it uses less digits than its factorization.

21315231502 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30723.

The product of its (nonzero) digits is 1800, while the sum is 25.

Adding to 21315231502 its reverse (20513251312), we get a palindrome (41828482814).

The spelling of 21315231502 in words is "twenty-one billion, three hundred fifteen million, two hundred thirty-one thousand, five hundred two".