33390721 has 16 divisors (see below), whose sum is σ = 41424768. Its totient is φ = 26208000.

The previous prime is 33390697. The next prime is 33390739. The reversal of 33390721 is 12709333.

It is not a de Polignac number, because 33390721 - 2¹⁹ = 32866433 is a prime.

It is a super-2 number, since 2×33390721² = 2229880497799682, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 33390721.

It is not an unprimeable number, because it can be changed into a prime (33390421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10521 + ... + 13321.

It is an arithmetic number, because the mean of its divisors is an integer number (2589048).

Almost surely, 2^33390721 is an apocalyptic number.

It is an amenable number.

33390721 is a deficient number, since it is larger than the sum of its proper divisors (8034047).

33390721 is a wasteful number, since it uses less digits than its factorization.

33390721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2952.

The product of its (nonzero) digits is 3402, while the sum is 28.

The square root of 33390721 is about 5778.4704723655. The cubic root of 33390721 is about 322.0143795901.

The spelling of 33390721 in words is "thirty-three million, three hundred ninety thousand, seven hundred twenty-one".