21938143977 has 8 divisors (see below), whose sum is σ = 32500954080. Its totient is φ = 14625429300.

The previous prime is 21938143961. The next prime is 21938143979. The reversal of 21938143977 is 77934183912.

21938143977 is a `hidden beast` number, since 219 + 38 + 1 + 4 + 397 + 7 = 666.

It is not a de Polignac number, because 21938143977 - 2⁴ = 21938143961 is a prime.

It is a super-2 number, since 2×21938143977² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21938143979) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 406261899 + ... + 406261952.

It is an arithmetic number, because the mean of its divisors is an integer number (4062619260).

Almost surely, 2^21938143977 is an apocalyptic number.

21938143977 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21938143977 is a deficient number, since it is larger than the sum of its proper divisors (10562810103).

21938143977 is an equidigital number, since it uses as much as digits as its factorization.

21938143977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 812523860 (or 812523854 counting only the distinct ones).

The product of its digits is 2286144, while the sum is 54.

The spelling of 21938143977 in words is "twenty-one billion, nine hundred thirty-eight million, one hundred forty-three thousand, nine hundred seventy-seven".