20191870 has 16 divisors (see below), whose sum is σ = 38258640. Its totient is φ = 7651584.

The previous prime is 20191867. The next prime is 20191879. The reversal of 20191870 is 7819102.

It is a super-2 number, since 2×20191870² = 815423228193800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20191879) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 52947 + ... + 53326.

It is an arithmetic number, because the mean of its divisors is an integer number (2391165).

Almost surely, 2^20191870 is an apocalyptic number.

20191870 is a deficient number, since it is larger than the sum of its proper divisors (18066770).

20191870 is a wasteful number, since it uses less digits than its factorization.

20191870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106299.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 20191870 is about 4493.5364691966. The cubic root of 20191870 is about 272.3070260724.

It can be divided in two parts, 20 and 191870, that added together give a triangular number (191890 = T₆₁₉).

The spelling of 20191870 in words is "twenty million, one hundred ninety-one thousand, eight hundred seventy".