21977923654 has 16 divisors (see below), whose sum is σ = 34446580992. Its totient is φ = 10497017608.

The previous prime is 21977923619. The next prime is 21977923661. The reversal of 21977923654 is 45632977912.

It is a junction number, because it is equal to n+sod(n) for n = 21977923595 and 21977923604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 287344 + ... + 355699.

It is an arithmetic number, because the mean of its divisors is an integer number (2152911312).

Almost surely, 2^21977923654 is an apocalyptic number.

21977923654 is a deficient number, since it is larger than the sum of its proper divisors (12468657338).

21977923654 is a wasteful number, since it uses less digits than its factorization.

21977923654 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 643811.

The product of its digits is 5715360, while the sum is 55.

The spelling of 21977923654 in words is "twenty-one billion, nine hundred seventy-seven million, nine hundred twenty-three thousand, six hundred fifty-four".