21379689 has 12 divisors (see below), whose sum is σ = 31539456. Its totient is φ = 13949592.

The previous prime is 21379681. The next prime is 21379697. The reversal of 21379689 is 98697312.

It is an interprime number because it is at equal distance from previous prime (21379681) and next prime (21379697).

It is not a de Polignac number, because 21379689 - 2³ = 21379681 is a prime.

It is a super-2 number, since 2×21379689² = 914182203473442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21379681) 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, 24849 + ... + 25694.

It is an arithmetic number, because the mean of its divisors is an integer number (2628288).

Almost surely, 2^21379689 is an apocalyptic number.

It is an amenable number.

21379689 is a deficient number, since it is larger than the sum of its proper divisors (10159767).

21379689 is a wasteful number, since it uses less digits than its factorization.

21379689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50596 (or 50593 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 21379689 is about 4623.8175785816. The cubic root of 21379689 is about 277.5452470656.

The spelling of 21379689 in words is "twenty-one million, three hundred seventy-nine thousand, six hundred eighty-nine".