21192406997 has 2 divisors, whose sum is σ = 21192406998. Its totient is φ = 21192406996.

The previous prime is 21192406981. The next prime is 21192407011. The reversal of 21192406997 is 79960429112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19236025636 + 1956381361 = 138694^2 + 44231^2 .

It is a cyclic number.

It is not a de Polignac number, because 21192406997 - 2⁴ = 21192406981 is a prime.

It is a super-2 number, since 2×21192406997² (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 (21192406597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10596203498 + 10596203499.

It is an arithmetic number, because the mean of its divisors is an integer number (10596203499).

Almost surely, 2^21192406997 is an apocalyptic number.

It is an amenable number.

21192406997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21192406997 is an equidigital number, since it uses as much as digits as its factorization.

21192406997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 489888, while the sum is 50.

The spelling of 21192406997 in words is "twenty-one billion, one hundred ninety-two million, four hundred six thousand, nine hundred ninety-seven".