1491636880 has 20 divisors (see below), whose sum is σ = 3468055932. Its totient is φ = 596654720.

The previous prime is 1491636877. The next prime is 1491636911. The reversal of 1491636880 is 886361941.

It can be written as a sum of positive squares in 2 ways, for example, as 1058331024 + 433305856 = 32532^2 + 20816^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×1491636880² = 4449961163552268800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1491636880.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9322651 + ... + 9322810.

Almost surely, 2^1491636880 is an apocalyptic number.

1491636880 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1491636880 is an abundant number, since it is smaller than the sum of its proper divisors (1976419052).

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

1491636880 is a wasteful number, since it uses less digits than its factorization.

1491636880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18645474 (or 18645468 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 46.

The square root of 1491636880 is about 38621.7151354002. The cubic root of 1491636880 is about 1142.5828581653.

The spelling of 1491636880 in words is "one billion, four hundred ninety-one million, six hundred thirty-six thousand, eight hundred eighty".