21396807 has 6 divisors (see below), whose sum is σ = 30906512. Its totient is φ = 14264532.

The previous prime is 21396803. The next prime is 21396827. The reversal of 21396807 is 70869312.

It is not a de Polignac number, because 21396807 - 2² = 21396803 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 (21396803) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1188703 + ... + 1188720.

Almost surely, 2^21396807 is an apocalyptic number.

21396807 is a deficient number, since it is larger than the sum of its proper divisors (9509705).

21396807 is a wasteful number, since it uses less digits than its factorization.

21396807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2377429 (or 2377426 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 21396807 is about 4625.6682760440. The cubic root of 21396807 is about 277.6193010288.

It can be divided in two parts, 213 and 96807, that added together give a triangular number (97020 = T₄₄₀).

The spelling of 21396807 in words is "twenty-one million, three hundred ninety-six thousand, eight hundred seven".