1491321216 has 256 divisors, whose sum is σ = 5101240320. Its totient is φ = 374630400.

The previous prime is 1491321211. The next prime is 1491321217. The reversal of 1491321216 is 6121231941.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1491321211) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 915795 + ... + 917421.

It is an arithmetic number, because the mean of its divisors is an integer number (19926720).

Almost surely, 2^1491321216 is an apocalyptic number.

1491321216 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 1491321216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2550620160).

1491321216 is an abundant number, since it is smaller than the sum of its proper divisors (3609919104).

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

1491321216 is a wasteful number, since it uses less digits than its factorization.

1491321216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1693 (or 1681 counting only the distinct ones).

The product of its digits is 2592, while the sum is 30.

The square root of 1491321216 is about 38617.6283062541. The cubic root of 1491321216 is about 1142.5022537132.

The spelling of 1491321216 in words is "one billion, four hundred ninety-one million, three hundred twenty-one thousand, two hundred sixteen".