21512393 has 8 divisors (see below), whose sum is σ = 24722880. Its totient is φ = 18336240.

The previous prime is 21512371. The next prime is 21512401. The reversal of 21512393 is 39321512.

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

It is a cyclic number.

It is not a de Polignac number, because 21512393 - 2⁸ = 21512137 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21512333) 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, 7223 + ... + 9756.

It is an arithmetic number, because the mean of its divisors is an integer number (3090360).

Almost surely, 2^21512393 is an apocalyptic number.

It is an amenable number.

21512393 is a deficient number, since it is larger than the sum of its proper divisors (3210487).

21512393 is a wasteful number, since it uses less digits than its factorization.

21512393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17167.

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

The square root of 21512393 is about 4638.1454267843. The cubic root of 21512393 is about 278.1183053222.

The spelling of 21512393 in words is "twenty-one million, five hundred twelve thousand, three hundred ninety-three".