1991951274 has 32 divisors (see below), whose sum is σ = 4137661440. Its totient is φ = 638836592.

The previous prime is 1991951243. The next prime is 1991951287. The reversal of 1991951274 is 4721591991.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43224 + ... + 76499.

It is an arithmetic number, because the mean of its divisors is an integer number (129301920).

Almost surely, 2^1991951274 is an apocalyptic number.

1991951274 is an abundant number, since it is smaller than the sum of its proper divisors (2145710166).

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

1991951274 is a wasteful number, since it uses less digits than its factorization.

1991951274 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119834.

The product of its digits is 204120, while the sum is 48.

The square root of 1991951274 is about 44631.2813394373. The cubic root of 1991951274 is about 1258.2286510326.

The spelling of 1991951274 in words is "one billion, nine hundred ninety-one million, nine hundred fifty-one thousand, two hundred seventy-four".