161621019 has 24 divisors (see below), whose sum is σ = 267451392. Its totient is φ = 92130480.

The previous prime is 161620957. The next prime is 161621029. The reversal of 161621019 is 910126161.

It is not a de Polignac number, because 161621019 - 2⁹ = 161620507 is a prime.

It is a super-2 number, since 2×161621019² = 52242707565196722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161620983 and 161621001.

It is not an unprimeable number, because it can be changed into a prime (161621029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25014 + ... + 30804.

It is an arithmetic number, because the mean of its divisors is an integer number (11143808).

Almost surely, 2^161621019 is an apocalyptic number.

161621019 is a deficient number, since it is larger than the sum of its proper divisors (105830373).

161621019 is a wasteful number, since it uses less digits than its factorization.

161621019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6247 (or 6244 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 161621019 is about 12713.0255643572. The cubic root of 161621019 is about 544.7107507580.

The spelling of 161621019 in words is "one hundred sixty-one million, six hundred twenty-one thousand, nineteen".