1621223161 has 4 divisors (see below), whose sum is σ = 1621690000. Its totient is φ = 1620756324.

The previous prime is 1621223143. The next prime is 1621223171. The reversal of 1621223161 is 1613221261.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1613221261 = 53 ⋅30438137.

It is a cyclic number.

It is not a de Polignac number, because 1621223161 - 2⁷ = 1621223033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1621223101) 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, 228171 + ... + 235168.

It is an arithmetic number, because the mean of its divisors is an integer number (405422500).

Almost surely, 2^1621223161 is an apocalyptic number.

It is an amenable number.

1621223161 is a deficient number, since it is larger than the sum of its proper divisors (466839).

1621223161 is an equidigital number, since it uses as much as digits as its factorization.

1621223161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 466838.

The product of its digits is 864, while the sum is 25.

The square root of 1621223161 is about 40264.4155675952. The cubic root of 1621223161 is about 1174.7558052368.

The spelling of 1621223161 in words is "one billion, six hundred twenty-one million, two hundred twenty-three thousand, one hundred sixty-one".