161477621 has 4 divisors (see below), whose sum is σ = 162170892. Its totient is φ = 160784352.

The previous prime is 161477567. The next prime is 161477623. The reversal of 161477621 is 126774161.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 126774161 = 10159 ⋅12479.

It can be written as a sum of positive squares in 2 ways, for example, as 56415121 + 105062500 = 7511^2 + 10250^2 .

It is a cyclic number.

It is not a de Polignac number, because 161477621 - 2¹⁰ = 161476597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161477623) 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, 346286 + ... + 346751.

It is an arithmetic number, because the mean of its divisors is an integer number (40542723).

Almost surely, 2^161477621 is an apocalyptic number.

It is an amenable number.

161477621 is a deficient number, since it is larger than the sum of its proper divisors (693271).

161477621 is an equidigital number, since it uses as much as digits as its factorization.

161477621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 693270.

The product of its digits is 14112, while the sum is 35.

The square root of 161477621 is about 12707.3845066560. The cubic root of 161477621 is about 544.5496051652.

The spelling of 161477621 in words is "one hundred sixty-one million, four hundred seventy-seven thousand, six hundred twenty-one".