161621547 has 4 divisors (see below), whose sum is σ = 215495400. Its totient is φ = 107747696.

The previous prime is 161621531. The next prime is 161621561. The reversal of 161621547 is 745126161.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161621547 - 2⁴ = 161621531 is a prime.

It is a super-2 number, since 2×161621547² = 52243048909346418, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161623547) 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, 26936922 + ... + 26936927.

It is an arithmetic number, because the mean of its divisors is an integer number (53873850).

Almost surely, 2^161621547 is an apocalyptic number.

161621547 is a deficient number, since it is larger than the sum of its proper divisors (53873853).

161621547 is an equidigital number, since it uses as much as digits as its factorization.

161621547 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53873852.

The product of its digits is 10080, while the sum is 33.

The square root of 161621547 is about 12713.0463304434. The cubic root of 161621547 is about 544.7113439296.

The spelling of 161621547 in words is "one hundred sixty-one million, six hundred twenty-one thousand, five hundred forty-seven".