161721942 has 8 divisors (see below), whose sum is σ = 323443896. Its totient is φ = 53907312.

The previous prime is 161721941. The next prime is 161721943. The reversal of 161721942 is 249127161.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (161721941) and next prime (161721943).

It is a sphenic number, since it is the product of 3 distinct primes.

161721942 is an admirable number.

It is a super-4 number, since 4×161721942⁴ (a number of 34 digits) contains 4444 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161721941) 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, 13476823 + ... + 13476834.

It is an arithmetic number, because the mean of its divisors is an integer number (40430487).

Almost surely, 2^161721942 is an apocalyptic number.

161721942 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161721942 is a wasteful number, since it uses less digits than its factorization.

161721942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26953662.

The product of its digits is 6048, while the sum is 33.

The square root of 161721942 is about 12716.9942203337. The cubic root of 161721942 is about 544.8241073102.

The spelling of 161721942 in words is "one hundred sixty-one million, seven hundred twenty-one thousand, nine hundred forty-two".