161620640 has 24 divisors (see below), whose sum is σ = 381829140. Its totient is φ = 64648192.

The previous prime is 161620633. The next prime is 161620663. The reversal of 161620640 is 46026161.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 160073104 + 1547536 = 12652^2 + 1244^2 .

It is a super-2 number, since 2×161620640² = 52242462548019200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 504905 + ... + 505224.

Almost surely, 2^161620640 is an apocalyptic number.

161620640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161620640 is an abundant number, since it is smaller than the sum of its proper divisors (220208500).

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

161620640 is a wasteful number, since it uses less digits than its factorization.

161620640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1010144 (or 1010136 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 161620640 is about 12713.0106583767. The cubic root of 161620640 is about 544.7103249769.

The spelling of 161620640 in words is "one hundred sixty-one million, six hundred twenty thousand, six hundred forty".