1581009408 has 320 divisors, whose sum is σ = 5261984640. Its totient is φ = 464486400.

The previous prime is 1581009403. The next prime is 1581009413. The reversal of 1581009408 is 8049001851.

It is an interprime number because it is at equal distance from previous prime (1581009403) and next prime (1581009413).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (1581009403) 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, 5626228 + ... + 5626508.

It is an arithmetic number, because the mean of its divisors is an integer number (16443702).

Almost surely, 2^1581009408 is an apocalyptic number.

1581009408 is a gapful number since it is divisible by the number (18) 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 1581009408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2630992320).

1581009408 is an abundant number, since it is smaller than the sum of its proper divisors (3680975232).

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

1581009408 is a wasteful number, since it uses less digits than its factorization.

1581009408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356 (or 334 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 1581009408 is about 39761.9090084971. The cubic root of 1581009408 is about 1164.9612635477.

The spelling of 1581009408 in words is "one billion, five hundred eighty-one million, nine thousand, four hundred eight".