21981152613 has 8 divisors (see below), whose sum is σ = 33495089728. Its totient is φ = 12560658624.

The previous prime is 21981152603. The next prime is 21981152617. The reversal of 21981152613 is 31625118912.

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

It is not a de Polignac number, because 21981152613 - 2⁵ = 21981152581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21981152617) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 523360756 + ... + 523360797.

It is an arithmetic number, because the mean of its divisors is an integer number (4186886216).

Almost surely, 2^21981152613 is an apocalyptic number.

It is an amenable number.

21981152613 is a deficient number, since it is larger than the sum of its proper divisors (11513937115).

21981152613 is a wasteful number, since it uses less digits than its factorization.

21981152613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1046721563.

The product of its digits is 25920, while the sum is 39.

It can be divided in two parts, 21981152 and 613, that added together give a triangular number (21981765 = T₆₆₃₀).

The spelling of 21981152613 in words is "twenty-one billion, nine hundred eighty-one million, one hundred fifty-two thousand, six hundred thirteen".