1991967372 has 144 divisors (see below), whose sum is σ = 5621324800. Its totient is φ = 592064640.

The previous prime is 1991967337. The next prime is 1991967377. The reversal of 1991967372 is 2737691991.

It is a happy number.

It is a super-2 number, since 2×1991967372² = 7935868022225172768, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1991967377) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 783279 + ... + 785817.

Almost surely, 2^1991967372 is an apocalyptic number.

1991967372 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1991967372, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2810662400).

1991967372 is an abundant number, since it is smaller than the sum of its proper divisors (3629357428).

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

1991967372 is a wasteful number, since it uses less digits than its factorization.

1991967372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2636 (or 2631 counting only the distinct ones).

The product of its digits is 1285956, while the sum is 54.

The square root of 1991967372 is about 44631.4616834358. The cubic root of 1991967372 is about 1258.2320404914.

The spelling of 1991967372 in words is "one billion, nine hundred ninety-one million, nine hundred sixty-seven thousand, three hundred seventy-two".