181620331 has 4 divisors (see below), whose sum is σ = 181710432. Its totient is φ = 181530232.

The previous prime is 181620323. The next prime is 181620371. The reversal of 181620331 is 133026181.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 181620331 - 2³ = 181620323 is a prime.

It is a super-2 number, since 2×181620331² = 65971889265099122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 181620296 and 181620305.

It is not an unprimeable number, because it can be changed into a prime (181620311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41956 + ... + 46081.

It is an arithmetic number, because the mean of its divisors is an integer number (45427608).

Almost surely, 2^181620331 is an apocalyptic number.

181620331 is a deficient number, since it is larger than the sum of its proper divisors (90101).

181620331 is an equidigital number, since it uses as much as digits as its factorization.

181620331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90100.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 181620331 is about 13476.6587476273. The cubic root of 181620331 is about 566.3107698734.

The spelling of 181620331 in words is "one hundred eighty-one million, six hundred twenty thousand, three hundred thirty-one".