1681291920 has 480 divisors, whose sum is σ = 6796814976. Its totient is φ = 339763200.

The previous prime is 1681291889. The next prime is 1681291933. The reversal of 1681291920 is 291921861.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 5303602 + ... + 5303918.

Almost surely, 2^1681291920 is an apocalyptic number.

1681291920 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 1681291920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3398407488).

1681291920 is an abundant number, since it is smaller than the sum of its proper divisors (5115523056).

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

1681291920 is a wasteful number, since it uses less digits than its factorization.

1681291920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399 (or 386 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 39.

The square root of 1681291920 is about 41003.5598454573. The cubic root of 1681291920 is about 1189.0890375402.

The spelling of 1681291920 in words is "one billion, six hundred eighty-one million, two hundred ninety-one thousand, nine hundred twenty".