1891351989 has 12 divisors (see below), whose sum is σ = 2735961696. Its totient is φ = 1259051112.

The previous prime is 1891351951. The next prime is 1891352003. The reversal of 1891351989 is 9891531981.

It is not a de Polignac number, because 1891351989 - 2⁹ = 1891351477 is a prime.

It is a super-2 number, since 2×1891351989² = 7154424692588512242, which contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1891351289) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 147697 + ... + 159990.

It is an arithmetic number, because the mean of its divisors is an integer number (227996808).

Almost surely, 2^1891351989 is an apocalyptic number.

It is an amenable number.

1891351989 is a deficient number, since it is larger than the sum of its proper divisors (844609707).

1891351989 is a wasteful number, since it uses less digits than its factorization.

1891351989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308376 (or 308373 counting only the distinct ones).

The product of its digits is 699840, while the sum is 54.

The square root of 1891351989 is about 43489.6768095602. The cubic root of 1891351989 is about 1236.6803309116.

The spelling of 1891351989 in words is "one billion, eight hundred ninety-one million, three hundred fifty-one thousand, nine hundred eighty-nine".