21680957629 has 2 divisors, whose sum is σ = 21680957630. Its totient is φ = 21680957628.

The previous prime is 21680957611. The next prime is 21680957657. The reversal of 21680957629 is 92675908612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12699036100 + 8981921529 = 112690^2 + 94773^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21680957629 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21680957629.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21680957329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10840478814 + 10840478815.

It is an arithmetic number, because the mean of its divisors is an integer number (10840478815).

Almost surely, 2^21680957629 is an apocalyptic number.

It is an amenable number.

21680957629 is a deficient number, since it is larger than the sum of its proper divisors (1).

21680957629 is an equidigital number, since it uses as much as digits as its factorization.

21680957629 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3265920, while the sum is 55.

The spelling of 21680957629 in words is "twenty-one billion, six hundred eighty million, nine hundred fifty-seven thousand, six hundred twenty-nine".