1620991736 has 144 divisors (see below), whose sum is σ = 3946221720. Its totient is φ = 618710400.

The previous prime is 1620991727. The next prime is 1620991751. The reversal of 1620991736 is 6371990261.

It is a super-2 number, since 2×1620991736² = 5255228416360587392, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 4897091 + ... + 4897421.

Almost surely, 2^1620991736 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1620991736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1973110860).

1620991736 is an abundant number, since it is smaller than the sum of its proper divisors (2325229984).

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

1620991736 is a wasteful number, since it uses less digits than its factorization.

1620991736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 426 (or 384 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 44.

The square root of 1620991736 is about 40261.5416495693. The cubic root of 1620991736 is about 1174.6999048923.

The spelling of 1620991736 in words is "one billion, six hundred twenty million, nine hundred ninety-one thousand, seven hundred thirty-six".