21397838401 has 2 divisors, whose sum is σ = 21397838402. Its totient is φ = 21397838400.

The previous prime is 21397838383. The next prime is 21397838411. The reversal of 21397838401 is 10483879312.

It is a Cunningham number, because it is equal to 146280²+1.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21397838400 + 1 = 146280^2 + 1^2 .

It is a cyclic number.

It is not a de Polignac number, because 21397838401 - 2⁵ = 21397838369 is a prime.

It is not a weakly prime, because it can be changed into another prime (21397838411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10698919200 + 10698919201.

It is an arithmetic number, because the mean of its divisors is an integer number (10698919201).

Almost surely, 2^21397838401 is an apocalyptic number.

It is an amenable number.

21397838401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21397838401 is an equidigital number, since it uses as much as digits as its factorization.

21397838401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 290304, while the sum is 46.

The spelling of 21397838401 in words is "twenty-one billion, three hundred ninety-seven million, eight hundred thirty-eight thousand, four hundred one".