161990757 has 6 divisors (see below), whose sum is σ = 233986662. Its totient is φ = 107993832.

The previous prime is 161990753. The next prime is 161990783. The reversal of 161990757 is 757099161.

161990757 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 158608836 + 3381921 = 12594^2 + 1839^2 .

It is not a de Polignac number, because 161990757 - 2² = 161990753 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161990753) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8999478 + ... + 8999495.

It is an arithmetic number, because the mean of its divisors is an integer number (38997777).

Almost surely, 2^161990757 is an apocalyptic number.

It is an amenable number.

161990757 is a deficient number, since it is larger than the sum of its proper divisors (71995905).

161990757 is a wasteful number, since it uses less digits than its factorization.

161990757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17998979 (or 17998976 counting only the distinct ones).

The product of its (nonzero) digits is 119070, while the sum is 45.

The square root of 161990757 is about 12727.5589568464. The cubic root of 161990757 is about 545.1258099700.

The spelling of 161990757 in words is "one hundred sixty-one million, nine hundred ninety thousand, seven hundred fifty-seven".