21877679 has 2 divisors, whose sum is σ = 21877680. Its totient is φ = 21877678.

The previous prime is 21877673. The next prime is 21877699. The reversal of 21877679 is 97677812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21877679 - 2⁴ = 21877663 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21877673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10938839 + 10938840.

It is an arithmetic number, because the mean of its divisors is an integer number (10938840).

Almost surely, 2^21877679 is an apocalyptic number.

21877679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21877679 is an equidigital number, since it uses as much as digits as its factorization.

21877679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 296352, while the sum is 47.

The square root of 21877679 is about 4677.3581218461. The cubic root of 21877679 is about 279.6836520740.

The spelling of 21877679 in words is "twenty-one million, eight hundred seventy-seven thousand, six hundred seventy-nine".