21631061197 has 2 divisors, whose sum is σ = 21631061198. Its totient is φ = 21631061196.

The previous prime is 21631061189. The next prime is 21631061201. The reversal of 21631061197 is 79116013612.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12880207081 + 8750854116 = 113491^2 + 93546^2 .

It is a cyclic number.

It is not a de Polignac number, because 21631061197 - 2³ = 21631061189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21631061147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10815530598 + 10815530599.

It is an arithmetic number, because the mean of its divisors is an integer number (10815530599).

Almost surely, 2^21631061197 is an apocalyptic number.

It is an amenable number.

21631061197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21631061197 is an equidigital number, since it uses as much as digits as its factorization.

21631061197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13608, while the sum is 37.

The spelling of 21631061197 in words is "twenty-one billion, six hundred thirty-one million, sixty-one thousand, one hundred ninety-seven".