21396051 has 6 divisors (see below), whose sum is σ = 30905420. Its totient is φ = 14264028.

The previous prime is 21396043. The next prime is 21396059. The reversal of 21396051 is 15069312.

21396051 is a `hidden beast` number, since 21 + 39 + 605 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (21396043) and next prime (21396059).

It is not a de Polignac number, because 21396051 - 2³ = 21396043 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21396059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1188661 + ... + 1188678.

Almost surely, 2^21396051 is an apocalyptic number.

21396051 is a deficient number, since it is larger than the sum of its proper divisors (9509369).

21396051 is a wasteful number, since it uses less digits than its factorization.

21396051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2377345 (or 2377342 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 21396051 is about 4625.5865574000. The cubic root of 21396051 is about 277.6160313406.

The spelling of 21396051 in words is "twenty-one million, three hundred ninety-six thousand, fifty-one".