1891918020 has 24 divisors (see below), whose sum is σ = 5297370624. Its totient is φ = 504511456.

The previous prime is 1891918009. The next prime is 1891918057. The reversal of 1891918020 is 208191981.

It is a self number, because there is not a number n which added to its sum of digits gives 1891918020.

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 in 7 ways as a sum of consecutive naturals, for example, 15765924 + ... + 15766043.

It is an arithmetic number, because the mean of its divisors is an integer number (220723776).

Almost surely, 2^1891918020 is an apocalyptic number.

1891918020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1891918020 is an abundant number, since it is smaller than the sum of its proper divisors (3405452604).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1891918020 is a wasteful number, since it uses less digits than its factorization.

1891918020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31531979 (or 31531977 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 39.

The square root of 1891918020 is about 43496.1839705508. The cubic root of 1891918020 is about 1236.8036870416.

The spelling of 1891918020 in words is "one billion, eight hundred ninety-one million, nine hundred eighteen thousand, twenty".