21048109631 has 4 divisors (see below), whose sum is σ = 21049299600. Its totient is φ = 21046919664.

The previous prime is 21048109627. The next prime is 21048109661. The reversal of 21048109631 is 13690184012.

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 21048109631 - 2² = 21048109627 is a prime.

It is a super-2 number, since 2×21048109631² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21048109591 and 21048109600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21048109661) 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, 568046 + ... + 603963.

It is an arithmetic number, because the mean of its divisors is an integer number (5262324900).

Almost surely, 2^21048109631 is an apocalyptic number.

21048109631 is a deficient number, since it is larger than the sum of its proper divisors (1189969).

21048109631 is a wasteful number, since it uses less digits than its factorization.

21048109631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1189968.

The product of its (nonzero) digits is 10368, while the sum is 35.

The spelling of 21048109631 in words is "twenty-one billion, forty-eight million, one hundred nine thousand, six hundred thirty-one".