161665502 has 4 divisors (see below), whose sum is σ = 242498256. Its totient is φ = 80832750.

The previous prime is 161665499. The next prime is 161665513. The reversal of 161665502 is 205566161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 205566161 = 12923 ⋅15907.

It is a super-2 number, since 2×161665502² = 52271469073824008, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40416374 + ... + 40416377.

It is an arithmetic number, because the mean of its divisors is an integer number (60624564).

Almost surely, 2^161665502 is an apocalyptic number.

161665502 is a deficient number, since it is larger than the sum of its proper divisors (80832754).

161665502 is an equidigital number, since it uses as much as digits as its factorization.

161665502 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80832753.

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 161665502 is about 12714.7749488538. The cubic root of 161665502 is about 544.7607198067.

The spelling of 161665502 in words is "one hundred sixty-one million, six hundred sixty-five thousand, five hundred two".