21997963658 has 16 divisors (see below), whose sum is σ = 35999014464. Its totient is φ = 9998422560.

The previous prime is 21997963651. The next prime is 21997963679. The reversal of 21997963658 is 85636979912.

It is a junction number, because it is equal to n+sod(n) for n = 21997963594 and 21997963603.

It is not an unprimeable number, because it can be changed into a prime (21997963651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 523091 + ... + 563577.

It is an arithmetic number, because the mean of its divisors is an integer number (2249938404).

Almost surely, 2^21997963658 is an apocalyptic number.

21997963658 is a deficient number, since it is larger than the sum of its proper divisors (14001050806).

21997963658 is a wasteful number, since it uses less digits than its factorization.

21997963658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65197.

The product of its digits is 44089920, while the sum is 65.

The spelling of 21997963658 in words is "twenty-one billion, nine hundred ninety-seven million, nine hundred sixty-three thousand, six hundred fifty-eight".