1891921090 has 16 divisors (see below), whose sum is σ = 3446489088. Its totient is φ = 747650416.

The previous prime is 1891921079. The next prime is 1891921099. The reversal of 1891921090 is 901291981.

It is not an unprimeable number, because it can be changed into a prime (1891921099) 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, 1138882 + ... + 1140541.

It is an arithmetic number, because the mean of its divisors is an integer number (215405568).

Almost surely, 2^1891921090 is an apocalyptic number.

1891921090 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1891921090 is a deficient number, since it is larger than the sum of its proper divisors (1554567998).

1891921090 is a wasteful number, since it uses less digits than its factorization.

1891921090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2279513.

The product of its (nonzero) digits is 11664, while the sum is 40.

The square root of 1891921090 is about 43496.2192609886. The cubic root of 1891921090 is about 1236.8043560250.

The spelling of 1891921090 in words is "one billion, eight hundred ninety-one million, nine hundred twenty-one thousand, ninety".