161621265 has 32 divisors (see below), whose sum is σ = 279135360. Its totient is φ = 79382016.

The previous prime is 161621209. The next prime is 161621267. The reversal of 161621265 is 562126161.

It is not a de Polignac number, because 161621265 - 2¹³ = 161613073 is a prime.

It is a super-2 number, since 2×161621265² = 52242866600400450, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161621267) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 124741 + ... + 126029.

It is an arithmetic number, because the mean of its divisors is an integer number (8722980).

Almost surely, 2^161621265 is an apocalyptic number.

161621265 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161621265 is a deficient number, since it is larger than the sum of its proper divisors (117514095).

161621265 is a wasteful number, since it uses less digits than its factorization.

161621265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1953.

The product of its digits is 4320, while the sum is 30.

The square root of 161621265 is about 12713.0352394698. The cubic root of 161621265 is about 544.7110271222.

The spelling of 161621265 in words is "one hundred sixty-one million, six hundred twenty-one thousand, two hundred sixty-five".