21642302197 has 2 divisors, whose sum is σ = 21642302198. Its totient is φ = 21642302196.

The previous prime is 21642302177. The next prime is 21642302221. The reversal of 21642302197 is 79120324612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17043563601 + 4598738596 = 130551^2 + 67814^2 .

It is a cyclic number.

It is not a de Polignac number, because 21642302197 - 2²⁷ = 21508084469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21642302167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10821151098 + 10821151099.

It is an arithmetic number, because the mean of its divisors is an integer number (10821151099).

Almost surely, 2^21642302197 is an apocalyptic number.

It is an amenable number.

21642302197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21642302197 is an equidigital number, since it uses as much as digits as its factorization.

21642302197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 37.

The spelling of 21642302197 in words is "twenty-one billion, six hundred forty-two million, three hundred two thousand, one hundred ninety-seven".