21097140929 has 2 divisors, whose sum is σ = 21097140930. Its totient is φ = 21097140928.

The previous prime is 21097140907. The next prime is 21097141007. The reversal of 21097140929 is 92904179012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20291432704 + 805708225 = 142448^2 + 28385^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21097140929 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21097140929.

It is not a weakly prime, because it can be changed into another prime (21097140329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10548570464 + 10548570465.

It is an arithmetic number, because the mean of its divisors is an integer number (10548570465).

Almost surely, 2^21097140929 is an apocalyptic number.

It is an amenable number.

21097140929 is a deficient number, since it is larger than the sum of its proper divisors (1).

21097140929 is an equidigital number, since it uses as much as digits as its factorization.

21097140929 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81648, while the sum is 44.

The spelling of 21097140929 in words is "twenty-one billion, ninety-seven million, one hundred forty thousand, nine hundred twenty-nine".