20857198 has 8 divisors (see below), whose sum is σ = 33126192. Its totient is φ = 9815136.

The previous prime is 20857183. The next prime is 20857211. The reversal of 20857198 is 89175802.

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

It is a super-2 number, since 2×20857198² = 870045416822408, 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 20857198.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 306690 + ... + 306757.

It is an arithmetic number, because the mean of its divisors is an integer number (4140774).

Almost surely, 2^20857198 is an apocalyptic number.

20857198 is a deficient number, since it is larger than the sum of its proper divisors (12268994).

20857198 is a wasteful number, since it uses less digits than its factorization.

20857198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 613466.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 20857198 is about 4566.9681409005. The cubic root of 20857198 is about 275.2656298398.

The spelling of 20857198 in words is "twenty million, eight hundred fifty-seven thousand, one hundred ninety-eight".