21379679 has 4 divisors (see below), whose sum is σ = 21475776. Its totient is φ = 21283584.

The previous prime is 21379663. The next prime is 21379681. The reversal of 21379679 is 97697312.

It is a happy number.

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 21379679 - 2⁴ = 21379663 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 (21379609) 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, 47714 + ... + 48159.

It is an arithmetic number, because the mean of its divisors is an integer number (5368944).

Almost surely, 2^21379679 is an apocalyptic number.

21379679 is a deficient number, since it is larger than the sum of its proper divisors (96097).

21379679 is an equidigital number, since it uses as much as digits as its factorization.

21379679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96096.

The product of its digits is 142884, while the sum is 44.

The square root of 21379679 is about 4623.8164972239. The cubic root of 21379679 is about 277.5452037932.

The spelling of 21379679 in words is "twenty-one million, three hundred seventy-nine thousand, six hundred seventy-nine".