21002771998 has 8 divisors (see below), whose sum is σ = 33927554808. Its totient is φ = 9693587064.

The previous prime is 21002771947. The next prime is 21002772013. The reversal of 21002771998 is 89917720012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21002771998² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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, 403899436 + ... + 403899487.

It is an arithmetic number, because the mean of its divisors is an integer number (4240944351).

Almost surely, 2^21002771998 is an apocalyptic number.

21002771998 is a deficient number, since it is larger than the sum of its proper divisors (12924782810).

21002771998 is a wasteful number, since it uses less digits than its factorization.

21002771998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 807798938.

The product of its (nonzero) digits is 127008, while the sum is 46.

It can be divided in two parts, 2100277 and 1998, that added together give a triangular number (2102275 = T₂₀₅₀).

The spelling of 21002771998 in words is "twenty-one billion, two million, seven hundred seventy-one thousand, nine hundred ninety-eight".