21916980997 has 4 divisors (see below), whose sum is σ = 22623980416. Its totient is φ = 21209981580.

The previous prime is 21916980977. The next prime is 21916981003. The reversal of 21916980997 is 79908961912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21916980997 - 2¹¹ = 21916978949 is a prime.

It is a super-2 number, since 2×21916980997² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21916980977) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 353499663 + ... + 353499724.

It is an arithmetic number, because the mean of its divisors is an integer number (5655995104).

Almost surely, 2^21916980997 is an apocalyptic number.

It is an amenable number.

21916980997 is a deficient number, since it is larger than the sum of its proper divisors (706999419).

21916980997 is an equidigital number, since it uses as much as digits as its factorization.

21916980997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 706999418.

The product of its (nonzero) digits is 4408992, while the sum is 61.

The spelling of 21916980997 in words is "twenty-one billion, nine hundred sixteen million, nine hundred eighty thousand, nine hundred ninety-seven".