21417901397 has 2 divisors, whose sum is σ = 21417901398. Its totient is φ = 21417901396.

The previous prime is 21417901387. The next prime is 21417901447. The reversal of 21417901397 is 79310971412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20525146756 + 892754641 = 143266^2 + 29879^2 .

It is a cyclic number.

It is not a de Polignac number, because 21417901397 - 2¹² = 21417897301 is a prime.

It is a super-2 number, since 2×21417901397² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21417901387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10708950698 + 10708950699.

It is an arithmetic number, because the mean of its divisors is an integer number (10708950699).

Almost surely, 2^21417901397 is an apocalyptic number.

It is an amenable number.

21417901397 is a deficient number, since it is larger than the sum of its proper divisors (1).

21417901397 is an equidigital number, since it uses as much as digits as its factorization.

21417901397 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 95256, while the sum is 44.

The spelling of 21417901397 in words is "twenty-one billion, four hundred seventeen million, nine hundred one thousand, three hundred ninety-seven".