21870679 has 2 divisors, whose sum is σ = 21870680. Its totient is φ = 21870678.

The previous prime is 21870659. The next prime is 21870713. The reversal of 21870679 is 97607812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21870679 - 2⁵ = 21870647 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21870659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10935339 + 10935340.

It is an arithmetic number, because the mean of its divisors is an integer number (10935340).

Almost surely, 2^21870679 is an apocalyptic number.

21870679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21870679 is an equidigital number, since it uses as much as digits as its factorization.

21870679 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 21870679 is about 4676.6097763230. The cubic root of 21870679 is about 279.6538196223.

The spelling of 21870679 in words is "twenty-one million, eight hundred seventy thousand, six hundred seventy-nine".