1991454528 has 224 divisors, whose sum is σ = 6527499264. Its totient is φ = 522805248.

The previous prime is 1991454499. The next prime is 1991454593. The reversal of 1991454528 is 8254541991.

It is a tau number, because it is divible by the number of its divisors (224).

It is a super-2 number, since 2×1991454528² = 7931782274183405568, which contains 22 as substring.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 981451 + ... + 983477.

Almost surely, 2^1991454528 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1991454528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3263749632).

1991454528 is an abundant number, since it is smaller than the sum of its proper divisors (4536044736).

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

1991454528 is a wasteful number, since it uses less digits than its factorization.

1991454528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2109 (or 2099 counting only the distinct ones).

The product of its digits is 518400, while the sum is 48.

The square root of 1991454528 is about 44625.7159942560. The cubic root of 1991454528 is about 1258.1240514172.

The spelling of 1991454528 in words is "one billion, nine hundred ninety-one million, four hundred fifty-four thousand, five hundred twenty-eight".