1991732064 has 96 divisors (see below), whose sum is σ = 6181297920. Its totient is φ = 549437952.

The previous prime is 1991732063. The next prime is 1991732107. The reversal of 1991732064 is 4602371991.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×1991732064² = 7933993229531400192, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991732063) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31614 + ... + 70589.

It is an arithmetic number, because the mean of its divisors is an integer number (64388520).

Almost surely, 2^1991732064 is an apocalyptic number.

1991732064 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1991732064 is an abundant number, since it is smaller than the sum of its proper divisors (4189565856).

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

1991732064 is a wasteful number, since it uses less digits than its factorization.

1991732064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102252 (or 102244 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 42.

The square root of 1991732064 is about 44628.8254830888. The cubic root of 1991732064 is about 1258.1824942107.

The spelling of 1991732064 in words is "one billion, nine hundred ninety-one million, seven hundred thirty-two thousand, sixty-four".