21019018775 has 24 divisors (see below), whose sum is σ = 26325243648. Its totient is φ = 16647020000.

The previous prime is 21019018723. The next prime is 21019018843. The reversal of 21019018775 is 57781091012.

It is not a de Polignac number, because 21019018775 - 2⁸ = 21019018519 is a prime.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 1404080 + ... + 1418970.

It is an arithmetic number, because the mean of its divisors is an integer number (1096885152).

Almost surely, 2^21019018775 is an apocalyptic number.

21019018775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21019018775 is a deficient number, since it is larger than the sum of its proper divisors (5306224873).

21019018775 is a wasteful number, since it uses less digits than its factorization.

21019018775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15463 (or 15458 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 41.

The spelling of 21019018775 in words is "twenty-one billion, nineteen million, eighteen thousand, seven hundred seventy-five".