21510349979 has 2 divisors, whose sum is σ = 21510349980. Its totient is φ = 21510349978.

The previous prime is 21510349963. The next prime is 21510350083. The reversal of 21510349979 is 97994301512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21510349979 - 2⁴ = 21510349963 is a prime.

It is not a weakly prime, because it can be changed into another prime (21510349919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10755174989 + 10755174990.

It is an arithmetic number, because the mean of its divisors is an integer number (10755174990).

Almost surely, 2^21510349979 is an apocalyptic number.

21510349979 is a deficient number, since it is larger than the sum of its proper divisors (1).

21510349979 is an equidigital number, since it uses as much as digits as its factorization.

21510349979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 612360, while the sum is 50.

The spelling of 21510349979 in words is "twenty-one billion, five hundred ten million, three hundred forty-nine thousand, nine hundred seventy-nine".