161474581921 has 3 divisors (see below), whose sum is σ = 161474983761. Its totient is φ = 161474180082.

The previous prime is 161474581903. The next prime is 161474581949. The reversal of 161474581921 is 129185474161.

The square root of 161474581921 is 401839.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 129185474161 = 2551 ⋅50641111.

It is not a de Polignac number, because 161474581921 - 2¹⁷ = 161474450849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161474581951) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 200920 + ... + 602758.

It is an arithmetic number, because the mean of its divisors is an integer number (53824994587).

Almost surely, 2^161474581921 is an apocalyptic number.

161474581921 is the 401839-th square number.

161474581921 is the 200920-th centered octagonal number.

It is an amenable number.

161474581921 is a deficient number, since it is larger than the sum of its proper divisors (401840).

161474581921 is an frugal number, since it uses more digits than its factorization.

161474581921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 803678 (or 401839 counting only the distinct ones).

The product of its digits is 483840, while the sum is 49.

Multiplying 161474581921 by its sum of digits (49), we get a square (7912254514129 = 2812873²).

The spelling of 161474581921 in words is "one hundred sixty-one billion, four hundred seventy-four million, five hundred eighty-one thousand, nine hundred twenty-one".