161635990 has 16 divisors (see below), whose sum is σ = 291163248. Its totient is φ = 64605856.

The previous prime is 161635967. The next prime is 161635993. The reversal of 161635990 is 99536161.

161635990 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×161635990² = 52252386526560200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161635993) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9924 + ... + 20536.

It is an arithmetic number, because the mean of its divisors is an integer number (18197703).

Almost surely, 2^161635990 is an apocalyptic number.

161635990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161635990 is a deficient number, since it is larger than the sum of its proper divisors (129527258).

161635990 is a wasteful number, since it uses less digits than its factorization.

161635990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12143.

The product of its (nonzero) digits is 43740, while the sum is 40.

The square root of 161635990 is about 12713.6143562718. The cubic root of 161635990 is about 544.7275691416.

The spelling of 161635990 in words is "one hundred sixty-one million, six hundred thirty-five thousand, nine hundred ninety".