161999420 has 24 divisors (see below), whose sum is σ = 371126448. Its totient is φ = 58908800.

The previous prime is 161999417. The next prime is 161999437. The reversal of 161999420 is 24999161.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 367961 + ... + 368400.

It is an arithmetic number, because the mean of its divisors is an integer number (15463602).

Almost surely, 2^161999420 is an apocalyptic number.

161999420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161999420 is an abundant number, since it is smaller than the sum of its proper divisors (209127028).

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

161999420 is a wasteful number, since it uses less digits than its factorization.

161999420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 736381 (or 736379 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 161999420 is about 12727.8992767856. The cubic root of 161999420 is about 545.1355272748.

The spelling of 161999420 in words is "one hundred sixty-one million, nine hundred ninety-nine thousand, four hundred twenty".