20197858 has 4 divisors (see below), whose sum is σ = 30296790. Its totient is φ = 10098928.

The previous prime is 20197843. The next prime is 20197861. The reversal of 20197858 is 85879102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 16024009 + 4173849 = 4003^2 + 2043^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 20197858.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5049463 + ... + 5049466.

Almost surely, 2^20197858 is an apocalyptic number.

20197858 is a deficient number, since it is larger than the sum of its proper divisors (10098932).

20197858 is a wasteful number, since it uses less digits than its factorization.

20197858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10098931.

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

The square root of 20197858 is about 4494.2027101589. The cubic root of 20197858 is about 272.3339414152. Note that the first 3 decimals are identical.

The spelling of 20197858 in words is "twenty million, one hundred ninety-seven thousand, eight hundred fifty-eight".