21973623997 has 6 divisors (see below), whose sum is σ = 23664478362. Its totient is φ = 20282851872.

The previous prime is 21973623977. The next prime is 21973624027. The reversal of 21973623997 is 79932637912.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 5139599481 + 16834024516 = 71691^2 + 129746^2 .

It is not a de Polignac number, because 21973623997 - 2⁷ = 21973623869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21973623977) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 513913 + ... + 555025.

It is an arithmetic number, because the mean of its divisors is an integer number (3944079727).

Almost surely, 2^21973623997 is an apocalyptic number.

It is an amenable number.

21973623997 is a deficient number, since it is larger than the sum of its proper divisors (1690854365).

21973623997 is an frugal number, since it uses more digits than its factorization.

21973623997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82239 (or 41126 counting only the distinct ones).

The product of its digits is 7715736, while the sum is 58.

The spelling of 21973623997 in words is "twenty-one billion, nine hundred seventy-three million, six hundred twenty-three thousand, nine hundred ninety-seven".