1581996920 has 64 divisors (see below), whose sum is σ = 4077112320. Its totient is φ = 541183104.

The previous prime is 1581996919. The next prime is 1581996953. The reversal of 1581996920 is 296991851.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 123539 + ... + 135741.

It is an arithmetic number, because the mean of its divisors is an integer number (63704880).

Almost surely, 2^1581996920 is an apocalyptic number.

1581996920 is a gapful number since it is divisible by the number (10) 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 1581996920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2038556160).

1581996920 is an abundant number, since it is smaller than the sum of its proper divisors (2495115400).

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

1581996920 is a wasteful number, since it uses less digits than its factorization.

1581996920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12684 (or 12680 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 50.

The square root of 1581996920 is about 39774.3248842768. The cubic root of 1581996920 is about 1165.2037613227.

The spelling of 1581996920 in words is "one billion, five hundred eighty-one million, nine hundred ninety-six thousand, nine hundred twenty".