1609972121 has 4 divisors (see below), whose sum is σ = 1616093952. Its totient is φ = 1603850292.

The previous prime is 1609972079. The next prime is 1609972127. The reversal of 1609972121 is 1212799061.

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: 1212799061 = 37 ⋅32778353.

It is a cyclic number.

It is not a de Polignac number, because 1609972121 - 2³⁰ = 536230297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1609972127) 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, 3060521 + ... + 3061046.

It is an arithmetic number, because the mean of its divisors is an integer number (404023488).

Almost surely, 2^1609972121 is an apocalyptic number.

It is an amenable number.

1609972121 is a deficient number, since it is larger than the sum of its proper divisors (6121831).

1609972121 is an equidigital number, since it uses as much as digits as its factorization.

1609972121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6121830.

The product of its (nonzero) digits is 13608, while the sum is 38.

The square root of 1609972121 is about 40124.4578904189. The cubic root of 1609972121 is about 1172.0319527626.

The spelling of 1609972121 in words is "one billion, six hundred nine million, nine hundred seventy-two thousand, one hundred twenty-one".