21791071852 has 48 divisors (see below), whose sum is σ = 44329063968. Its totient is φ = 9262955520.

The previous prime is 21791071843. The next prime is 21791071871. The reversal of 21791071852 is 25817019712.

It is a junction number, because it is equal to n+sod(n) for n = 21791071799 and 21791071808.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24658 + ... + 210214.

It is an arithmetic number, because the mean of its divisors is an integer number (923522166).

Almost surely, 2^21791071852 is an apocalyptic number.

21791071852 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21791071852 is an abundant number, since it is smaller than the sum of its proper divisors (22537992116).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21791071852 is a wasteful number, since it uses less digits than its factorization.

21791071852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185746 (or 185744 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 43.

The spelling of 21791071852 in words is "twenty-one billion, seven hundred ninety-one million, seventy-one thousand, eight hundred fifty-two".