21396352723 has 2 divisors, whose sum is σ = 21396352724. Its totient is φ = 21396352722.

The previous prime is 21396352693. The next prime is 21396352729. The reversal of 21396352723 is 32725369312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21396352723 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21396352723.

It is not a weakly prime, because it can be changed into another prime (21396352729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10698176361 + 10698176362.

It is an arithmetic number, because the mean of its divisors is an integer number (10698176362).

Almost surely, 2^21396352723 is an apocalyptic number.

21396352723 is a deficient number, since it is larger than the sum of its proper divisors (1).

21396352723 is an equidigital number, since it uses as much as digits as its factorization.

21396352723 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 408240, while the sum is 43.

The spelling of 21396352723 in words is "twenty-one billion, three hundred ninety-six million, three hundred fifty-two thousand, seven hundred twenty-three".