21040679 has 16 divisors (see below), whose sum is σ = 24968736. Its totient is φ = 17510400.

The previous prime is 21040673. The next prime is 21040681. The reversal of 21040679 is 97604012.

It is a cyclic number.

It is not a de Polignac number, because 21040679 - 2²⁰ = 19992103 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 (21040673) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5399 + ... + 8439.

It is an arithmetic number, because the mean of its divisors is an integer number (1560546).

Almost surely, 2^21040679 is an apocalyptic number.

21040679 is a deficient number, since it is larger than the sum of its proper divisors (3928057).

21040679 is a wasteful number, since it uses less digits than its factorization.

21040679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3106.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 21040679 is about 4587.0119903920. The cubic root of 21040679 is about 276.0704460310.

The spelling of 21040679 in words is "twenty-one million, forty thousand, six hundred seventy-nine".