21771421988 has 12 divisors (see below), whose sum is σ = 38224094832. Its totient is φ = 10850252040.

The previous prime is 21771421979. The next prime is 21771422021. The reversal of 21771421988 is 88912417712.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8863358 + ... + 8865813.

It is an arithmetic number, because the mean of its divisors is an integer number (3185341236).

Almost surely, 2^21771421988 is an apocalyptic number.

It is an amenable number.

21771421988 is a deficient number, since it is larger than the sum of its proper divisors (16452672844).

21771421988 is a wasteful number, since it uses less digits than its factorization.

21771421988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17729482 (or 17729480 counting only the distinct ones).

The product of its digits is 451584, while the sum is 50.

The spelling of 21771421988 in words is "twenty-one billion, seven hundred seventy-one million, four hundred twenty-one thousand, nine hundred eighty-eight".