331220021 has 8 divisors (see below), whose sum is σ = 361972800. Its totient is φ = 300574240.

The previous prime is 331220009. The next prime is 331220023. The reversal of 331220021 is 120022133.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 331220021 - 2⁶ = 331219957 is a prime.

It is a super-2 number, since 2×331220021² = 219413404622480882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 331219978 and 331220005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (331220023) 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, 20201 + ... + 32718.

It is an arithmetic number, because the mean of its divisors is an integer number (45246600).

Almost surely, 2^331220021 is an apocalyptic number.

It is an amenable number.

331220021 is a deficient number, since it is larger than the sum of its proper divisors (30752779).

331220021 is a wasteful number, since it uses less digits than its factorization.

331220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53499.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 331220021 is about 18199.4511180969. The cubic root of 331220021 is about 691.8928778518.

Adding to 331220021 its reverse (120022133), we get a palindrome (451242154).

The spelling of 331220021 in words is "three hundred thirty-one million, two hundred twenty thousand, twenty-one".