161553620 has 24 divisors (see below), whose sum is σ = 344826888. Its totient is φ = 63561600.

The previous prime is 161553619. The next prime is 161553647. The reversal of 161553620 is 26355161.

It can be written as a sum of positive squares in 4 ways, for example, as 10214416 + 151339204 = 3196^2 + 12302^2 .

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 64991 + ... + 67430.

It is an arithmetic number, because the mean of its divisors is an integer number (14367787).

Almost surely, 2^161553620 is an apocalyptic number.

161553620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161553620 is an abundant number, since it is smaller than the sum of its proper divisors (183273268).

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

161553620 is a wasteful number, since it uses less digits than its factorization.

161553620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132491 (or 132489 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 161553620 is about 12710.3745027438. The cubic root of 161553620 is about 544.6350220262.

The spelling of 161553620 in words is "one hundred sixty-one million, five hundred fifty-three thousand, six hundred twenty".