33221721 has 8 divisors (see below), whose sum is σ = 47703040. Its totient is φ = 20444112.

The previous prime is 33221711. The next prime is 33221737. The reversal of 33221721 is 12712233.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 33221721 - 2⁷ = 33221593 is a prime.

It is a super-2 number, since 2×33221721² = 2207365492403682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (33221701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 425881 + ... + 425958.

It is an arithmetic number, because the mean of its divisors is an integer number (5962880).

Almost surely, 2^33221721 is an apocalyptic number.

It is an amenable number.

33221721 is a deficient number, since it is larger than the sum of its proper divisors (14481319).

33221721 is a wasteful number, since it uses less digits than its factorization.

33221721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 851855.

The product of its digits is 504, while the sum is 21.

The square root of 33221721 is about 5763.8286754552. The cubic root of 33221721 is about 321.4701914642.

Adding to 33221721 its reverse (12712233), we get a palindrome (45933954).

The spelling of 33221721 in words is "thirty-three million, two hundred twenty-one thousand, seven hundred twenty-one".