1891722988 has 12 divisors (see below), whose sum is σ = 3318419160. Its totient is φ = 943603232.

The previous prime is 1891722979. The next prime is 1891722997. The reversal of 1891722988 is 8892271981.

It is an interprime number because it is at equal distance from previous prime (1891722979) and next prime (1891722997).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 562681 + ... + 566032.

It is an arithmetic number, because the mean of its divisors is an integer number (276534930).

Almost surely, 2^1891722988 is an apocalyptic number.

It is an amenable number.

1891722988 is a deficient number, since it is larger than the sum of its proper divisors (1426696172).

1891722988 is a wasteful number, since it uses less digits than its factorization.

1891722988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1129136 (or 1129134 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 55.

The square root of 1891722988 is about 43493.9419689685. The cubic root of 1891722988 is about 1236.7611861539.

It can be divided in two parts, 18917 and 22988, that added together give a triangular number (41905 = T₂₈₉).

The spelling of 1891722988 in words is "one billion, eight hundred ninety-one million, seven hundred twenty-two thousand, nine hundred eighty-eight".