21392199397 has 2 divisors, whose sum is σ = 21392199398. Its totient is φ = 21392199396.

The previous prime is 21392199383. The next prime is 21392199457. The reversal of 21392199397 is 79399129312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21362453281 + 29746116 = 146159^2 + 5454^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21392199397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21392199497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10696099698 + 10696099699.

It is an arithmetic number, because the mean of its divisors is an integer number (10696099699).

Almost surely, 2^21392199397 is an apocalyptic number.

It is an amenable number.

21392199397 is a deficient number, since it is larger than the sum of its proper divisors (1).

21392199397 is an equidigital number, since it uses as much as digits as its factorization.

21392199397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1653372, while the sum is 55.

The spelling of 21392199397 in words is "twenty-one billion, three hundred ninety-two million, one hundred ninety-nine thousand, three hundred ninety-seven".