21513293 has 4 divisors (see below), whose sum is σ = 21621600. Its totient is φ = 21404988.

The previous prime is 21513277. The next prime is 21513299. The reversal of 21513293 is 39231512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21513293 - 2⁴ = 21513277 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 (21513299) 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, 53855 + ... + 54252.

It is an arithmetic number, because the mean of its divisors is an integer number (5405400).

Almost surely, 2^21513293 is an apocalyptic number.

It is an amenable number.

21513293 is a deficient number, since it is larger than the sum of its proper divisors (108307).

21513293 is a wasteful number, since it uses less digits than its factorization.

21513293 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108306.

The product of its digits is 1620, while the sum is 26.

The square root of 21513293 is about 4638.2424473070. The cubic root of 21513293 is about 278.1221837530.

The spelling of 21513293 in words is "twenty-one million, five hundred thirteen thousand, two hundred ninety-three".