21315123254 has 8 divisors (see below), whose sum is σ = 31994724168. Its totient is φ = 10650215200.

The previous prime is 21315123253. The next prime is 21315123299. The reversal of 21315123254 is 45232151312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315123253) 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, 3669587 + ... + 3675390.

It is an arithmetic number, because the mean of its divisors is an integer number (3999340521).

Almost surely, 2^21315123254 is an apocalyptic number.

21315123254 is a deficient number, since it is larger than the sum of its proper divisors (10679600914).

21315123254 is a wasteful number, since it uses less digits than its factorization.

21315123254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7346430.

The product of its digits is 7200, while the sum is 29.

Adding to 21315123254 its reverse (45232151312), we get a palindrome (66547274566).

The spelling of 21315123254 in words is "twenty-one billion, three hundred fifteen million, one hundred twenty-three thousand, two hundred fifty-four".