1621122161 has 4 divisors (see below), whose sum is σ = 1706444400. Its totient is φ = 1535799924.

The previous prime is 1621122157. The next prime is 1621122163. The reversal of 1621122161 is 1612211261.

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.

It is a cyclic number.

It is not a de Polignac number, because 1621122161 - 2² = 1621122157 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1621122163) 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, 42661091 + ... + 42661128.

It is an arithmetic number, because the mean of its divisors is an integer number (426611100).

Almost surely, 2^1621122161 is an apocalyptic number.

It is an amenable number.

1621122161 is a deficient number, since it is larger than the sum of its proper divisors (85322239).

1621122161 is an equidigital number, since it uses as much as digits as its factorization.

1621122161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85322238.

The product of its digits is 288, while the sum is 23.

The square root of 1621122161 is about 40263.1613388715. The cubic root of 1621122161 is about 1174.7314095000.

The spelling of 1621122161 in words is "one billion, six hundred twenty-one million, one hundred twenty-two thousand, one hundred sixty-one".