20471998 has 8 divisors (see below), whose sum is σ = 31140720. Its totient is φ = 10091760.

The previous prime is 20471977. The next prime is 20472007. The reversal of 20471998 is 89917402.

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

It is a super-2 number, since 2×20471998² = 838205404224008, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20471998.

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, 71943 + ... + 72226.

It is an arithmetic number, because the mean of its divisors is an integer number (3892590).

Almost surely, 2^20471998 is an apocalyptic number.

20471998 is the 2419-th centered heptagonal number.

20471998 is a deficient number, since it is larger than the sum of its proper divisors (10668722).

20471998 is a wasteful number, since it uses less digits than its factorization.

20471998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144242.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 20471998 is about 4524.5992087698. The cubic root of 20471998 is about 273.5605134213.

The spelling of 20471998 in words is "twenty million, four hundred seventy-one thousand, nine hundred ninety-eight".