33136721 has 4 divisors (see below), whose sum is σ = 34577472. Its totient is φ = 31695972.

The previous prime is 33136717. The next prime is 33136729. The reversal of 33136721 is 12763133.

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 33136721 - 2² = 33136717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (33136729) 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, 720341 + ... + 720386.

It is an arithmetic number, because the mean of its divisors is an integer number (8644368).

Almost surely, 2^33136721 is an apocalyptic number.

It is an amenable number.

33136721 is a deficient number, since it is larger than the sum of its proper divisors (1440751).

33136721 is a wasteful number, since it uses less digits than its factorization.

33136721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1440750.

The product of its digits is 2268, while the sum is 26.

The square root of 33136721 is about 5756.4503819628. The cubic root of 33136721 is about 321.1957896283.

Adding to 33136721 its reverse (12763133), we get a palindrome (45899854).

The spelling of 33136721 in words is "thirty-three million, one hundred thirty-six thousand, seven hundred twenty-one".