161221654 has 48 divisors (see below), whose sum is σ = 278991216. Its totient is φ = 69264000.

The previous prime is 161221603. The next prime is 161221667. The reversal of 161221654 is 456122161.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1596204 + ... + 1596304.

It is an arithmetic number, because the mean of its divisors is an integer number (5812317).

Almost surely, 2^161221654 is an apocalyptic number.

161221654 is a deficient number, since it is larger than the sum of its proper divisors (117769562).

161221654 is a wasteful number, since it uses less digits than its factorization.

161221654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241 (or 204 counting only the distinct ones).

The product of its digits is 2880, while the sum is 28.

The square root of 161221654 is about 12697.3089274854. The cubic root of 161221654 is about 544.2617212205.

The spelling of 161221654 in words is "one hundred sixty-one million, two hundred twenty-one thousand, six hundred fifty-four".