21019018776 has 64 divisors (see below), whose sum is σ = 60067111680. Its totient is φ = 6004156800.

The previous prime is 21019018723. The next prime is 21019018843. The reversal of 21019018776 is 67781091012.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1014715 + ... + 1035221.

It is an arithmetic number, because the mean of its divisors is an integer number (938548620).

Almost surely, 2^21019018776 is an apocalyptic number.

It is an amenable number.

21019018776 is an abundant number, since it is smaller than the sum of its proper divisors (39048092904).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21019018776 is a wasteful number, since it uses less digits than its factorization.

21019018776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26624 (or 26620 counting only the distinct ones).

The product of its (nonzero) digits is 42336, while the sum is 42.

The spelling of 21019018776 in words is "twenty-one billion, nineteen million, eighteen thousand, seven hundred seventy-six".