21939708652461 has 8 divisors (see below), whose sum is σ = 32503272077760. Its totient is φ = 14626472434956.

The previous prime is 21939708652457. The next prime is 21939708652469. The reversal of 21939708652461 is 16425680793912.

21939708652461 is a `hidden beast` number, since 2 + 1 + 9 + 3 + 97 + 0 + 86 + 5 + 2 + 461 = 666.

It is not a de Polignac number, because 21939708652461 - 2² = 21939708652457 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21939708652469) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 406290900945 + ... + 406290900998.

It is an arithmetic number, because the mean of its divisors is an integer number (4062909009720).

It is a 1-persistent number, because it is pandigital, but 2⋅21939708652461 = 43879417304922 is not.

Almost surely, 2^{21939708652461} is an apocalyptic number.

It is an amenable number.

21939708652461 is a deficient number, since it is larger than the sum of its proper divisors (10563563425299).

21939708652461 is an equidigital number, since it uses as much as digits as its factorization.

21939708652461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 812581801952 (or 812581801946 counting only the distinct ones).

The product of its (nonzero) digits is 39191040, while the sum is 63.

The spelling of 21939708652461 in words is "twenty-one trillion, nine hundred thirty-nine billion, seven hundred eight million, six hundred fifty-two thousand, four hundred sixty-one".