1491021216 has 192 divisors, whose sum is σ = 4523904000. Its totient is φ = 477404928.

The previous prime is 1491021209. The next prime is 1491021221. The reversal of 1491021216 is 6121201941.

1491021216 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 1491021216.

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, 2488885 + ... + 2489483.

It is an arithmetic number, because the mean of its divisors is an integer number (23562000).

Almost surely, 2^1491021216 is an apocalyptic number.

1491021216 is a gapful number since it is divisible by the number (16) 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 1491021216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2261952000).

1491021216 is an abundant number, since it is smaller than the sum of its proper divisors (3032882784).

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

1491021216 is a wasteful number, since it uses less digits than its factorization.

1491021216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 728 (or 714 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 1491021216 is about 38613.7438744290. The cubic root of 1491021216 is about 1142.4256385038.

The spelling of 1491021216 in words is "one billion, four hundred ninety-one million, twenty-one thousand, two hundred sixteen".