21680469 has 12 divisors (see below), whose sum is σ = 31370976. Its totient is φ = 14428392.

The previous prime is 21680459. The next prime is 21680473. The reversal of 21680469 is 96408612.

It is not a de Polignac number, because 21680469 - 2⁷ = 21680341 is a prime.

It is a super-2 number, since 2×21680469² = 940085472119922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21680419) 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, 4384 + ... + 7910.

It is an arithmetic number, because the mean of its divisors is an integer number (2614248).

Almost surely, 2^21680469 is an apocalyptic number.

It is an amenable number.

21680469 is a deficient number, since it is larger than the sum of its proper divisors (9690507).

21680469 is a wasteful number, since it uses less digits than its factorization.

21680469 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4216 (or 4213 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 21680469 is about 4656.2290536442. The cubic root of 21680469 is about 278.8407384891.

The spelling of 21680469 in words is "twenty-one million, six hundred eighty thousand, four hundred sixty-nine".