21534679 has 4 divisors (see below), whose sum is σ = 21756784. Its totient is φ = 21312576.

The previous prime is 21534659. The next prime is 21534683. The reversal of 21534679 is 97643512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21534679 - 2⁷ = 21534551 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 (21534659) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110907 + ... + 111100.

It is an arithmetic number, because the mean of its divisors is an integer number (5439196).

Almost surely, 2^21534679 is an apocalyptic number.

21534679 is a deficient number, since it is larger than the sum of its proper divisors (222105).

21534679 is an equidigital number, since it uses as much as digits as its factorization.

21534679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222104.

The product of its digits is 45360, while the sum is 37.

The square root of 21534679 is about 4640.5472737599. The cubic root of 21534679 is about 278.2143120819.

The spelling of 21534679 in words is "twenty-one million, five hundred thirty-four thousand, six hundred seventy-nine".