161621734 has 4 divisors (see below), whose sum is σ = 242432604. Its totient is φ = 80810866.

The previous prime is 161621731. The next prime is 161621743. The reversal of 161621734 is 437126161.

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

It is a super-2 number, since 2×161621734² = 52243169802333512, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161621696 and 161621705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161621731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40405432 + ... + 40405435.

It is an arithmetic number, because the mean of its divisors is an integer number (60608151).

Almost surely, 2^161621734 is an apocalyptic number.

161621734 is a deficient number, since it is larger than the sum of its proper divisors (80810870).

161621734 is an equidigital number, since it uses as much as digits as its factorization.

161621734 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80810869.

The product of its digits is 6048, while the sum is 31.

The square root of 161621734 is about 12713.0536850908. The cubic root of 161621734 is about 544.7115540109.

Adding to 161621734 its reverse (437126161), we get a palindrome (598747895).

The spelling of 161621734 in words is "one hundred sixty-one million, six hundred twenty-one thousand, seven hundred thirty-four".