33121561 has 4 divisors (see below), whose sum is σ = 36132624. Its totient is φ = 30110500.

The previous prime is 33121553. The next prime is 33121589. The reversal of 33121561 is 16512133.

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.

It is a cyclic number.

It is not a de Polignac number, because 33121561 - 2³ = 33121553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (33121591) 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, 1505515 + ... + 1505536.

It is an arithmetic number, because the mean of its divisors is an integer number (9033156).

Almost surely, 2^33121561 is an apocalyptic number.

It is an amenable number.

33121561 is a deficient number, since it is larger than the sum of its proper divisors (3011063).

33121561 is a wasteful number, since it uses less digits than its factorization.

33121561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3011062.

The product of its digits is 540, while the sum is 22.

The square root of 33121561 is about 5755.1334476274. The cubic root of 33121561 is about 321.1467999598.

Adding to 33121561 its reverse (16512133), we get a palindrome (49633694).

The spelling of 33121561 in words is "thirty-three million, one hundred twenty-one thousand, five hundred sixty-one".