21673679 has 4 divisors (see below), whose sum is σ = 21722400. Its totient is φ = 21624960.

The previous prime is 21673651. The next prime is 21673703. The reversal of 21673679 is 97637612.

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 21673679 - 2⁸ = 21673423 is a prime.

It is a super-2 number, since 2×21673679² = 939496722790082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21670679) 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, 23687 + ... + 24584.

It is an arithmetic number, because the mean of its divisors is an integer number (5430600).

Almost surely, 2^21673679 is an apocalyptic number.

21673679 is a deficient number, since it is larger than the sum of its proper divisors (48721).

21673679 is an equidigital number, since it uses as much as digits as its factorization.

21673679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48720.

The product of its digits is 95256, while the sum is 41.

The square root of 21673679 is about 4655.4998657502. The cubic root of 21673679 is about 278.8116258608.

The spelling of 21673679 in words is "twenty-one million, six hundred seventy-three thousand, six hundred seventy-nine".