21432729667 has 2 divisors, whose sum is σ = 21432729668. Its totient is φ = 21432729666.

The previous prime is 21432729649. The next prime is 21432729683. The reversal of 21432729667 is 76692723412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21432729667 - 2²⁷ = 21298511939 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21432729667.

It is not a weakly prime, because it can be changed into another prime (21432720667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10716364833 + 10716364834.

It is an arithmetic number, because the mean of its divisors is an integer number (10716364834).

Almost surely, 2^21432729667 is an apocalyptic number.

21432729667 is a deficient number, since it is larger than the sum of its proper divisors (1).

21432729667 is an equidigital number, since it uses as much as digits as its factorization.

21432729667 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1524096, while the sum is 49.

The spelling of 21432729667 in words is "twenty-one billion, four hundred thirty-two million, seven hundred twenty-nine thousand, six hundred sixty-seven".