21980513 has 2 divisors, whose sum is σ = 21980514. Its totient is φ = 21980512.

The previous prime is 21980467. The next prime is 21980561. The reversal of 21980513 is 31508912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21967969 + 12544 = 4687^2 + 112^2 .

It is a cyclic number.

It is not a de Polignac number, because 21980513 - 2⁶ = 21980449 is a prime.

It is not a weakly prime, because it can be changed into another prime (21980593) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10990256 + 10990257.

It is an arithmetic number, because the mean of its divisors is an integer number (10990257).

Almost surely, 2^21980513 is an apocalyptic number.

It is an amenable number.

21980513 is a deficient number, since it is larger than the sum of its proper divisors (1).

21980513 is an equidigital number, since it uses as much as digits as its factorization.

21980513 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 21980513 is about 4688.3379784312. The cubic root of 21980513 is about 280.1211762922.

The spelling of 21980513 in words is "twenty-one million, nine hundred eighty thousand, five hundred thirteen".