21423197390429 has 2 divisors, whose sum is σ = 21423197390430. Its totient is φ = 21423197390428.

The previous prime is 21423197390369. The next prime is 21423197390467. The reversal of 21423197390429 is 92409379132412.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21402142800025 + 21054590404 = 4626245^2 + 145102^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21423197390429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21423197390479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711598695214 + 10711598695215.

It is an arithmetic number, because the mean of its divisors is an integer number (10711598695215).

Almost surely, 2^{21423197390429} is an apocalyptic number.

It is an amenable number.

21423197390429 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423197390429 is an equidigital number, since it uses as much as digits as its factorization.

21423197390429 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5878656, while the sum is 56.

The spelling of 21423197390429 in words is "twenty-one trillion, four hundred twenty-three billion, one hundred ninety-seven million, three hundred ninety thousand, four hundred twenty-nine".