21513793 has 12 divisors (see below), whose sum is σ = 25116480. Its totient is φ = 18373992.

The previous prime is 21513787. The next prime is 21513797. The reversal of 21513793 is 39731512.

It is not a de Polignac number, because 21513793 - 2²¹ = 19416641 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 (21513797) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16980 + ... + 18202.

It is an arithmetic number, because the mean of its divisors is an integer number (2093040).

Almost surely, 2^21513793 is an apocalyptic number.

It is an amenable number.

21513793 is a deficient number, since it is larger than the sum of its proper divisors (3602687).

21513793 is a wasteful number, since it uses less digits than its factorization.

21513793 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1596 (or 1589 counting only the distinct ones).

The product of its digits is 5670, while the sum is 31.

The square root of 21513793 is about 4638.2963467204. The cubic root of 21513793 is about 278.1243383900.

The spelling of 21513793 in words is "twenty-one million, five hundred thirteen thousand, seven hundred ninety-three".