161649478 has 4 divisors (see below), whose sum is σ = 242474220. Its totient is φ = 80824738.

The previous prime is 161649461. The next prime is 161649503. The reversal of 161649478 is 874946161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 874946161 = 109 ⋅8027029.

It is a super-2 number, since 2×161649478² = 52261107475344968, 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, 40412368 + ... + 40412371.

It is an arithmetic number, because the mean of its divisors is an integer number (60618555).

Almost surely, 2^161649478 is an apocalyptic number.

161649478 is a deficient number, since it is larger than the sum of its proper divisors (80824742).

161649478 is an equidigital number, since it uses as much as digits as its factorization.

161649478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80824741.

The product of its digits is 290304, while the sum is 46.

The square root of 161649478 is about 12714.1448001822. The cubic root of 161649478 is about 544.7427206374.

The spelling of 161649478 in words is "one hundred sixty-one million, six hundred forty-nine thousand, four hundred seventy-eight".