21931686701 has 2 divisors, whose sum is σ = 21931686702. Its totient is φ = 21931686700.

The previous prime is 21931686661. The next prime is 21931686703. The reversal of 21931686701 is 10768613912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14196484201 + 7735202500 = 119149^2 + 87950^2 .

It is a cyclic number.

It is not a de Polignac number, because 21931686701 - 2¹⁴ = 21931670317 is a prime.

Together with 21931686703, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21931686703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10965843350 + 10965843351.

It is an arithmetic number, because the mean of its divisors is an integer number (10965843351).

Almost surely, 2^21931686701 is an apocalyptic number.

It is an amenable number.

21931686701 is a deficient number, since it is larger than the sum of its proper divisors (1).

21931686701 is an equidigital number, since it uses as much as digits as its factorization.

21931686701 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108864, while the sum is 44.

The spelling of 21931686701 in words is "twenty-one billion, nine hundred thirty-one million, six hundred eighty-six thousand, seven hundred one".