1220312021 has 4 divisors (see below), whose sum is σ = 1220540544. Its totient is φ = 1220083500.

The previous prime is 1220312017. The next prime is 1220312033. The reversal of 1220312021 is 1202130221.

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 1220312021 - 2² = 1220312017 is a prime.

It is a super-2 number, since 2×1220312021² = 2978322857194208882, 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 = 1220311987 and 1220312005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220312011) 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, 106055 + ... + 116996.

It is an arithmetic number, because the mean of its divisors is an integer number (305135136).

Almost surely, 2^1220312021 is an apocalyptic number.

It is an amenable number.

1220312021 is a deficient number, since it is larger than the sum of its proper divisors (228523).

1220312021 is an equidigital number, since it uses as much as digits as its factorization.

1220312021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228522.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 1220312021 is about 34932.9646752176. The cubic root of 1220312021 is about 1068.6208162953.

Adding to 1220312021 its reverse (1202130221), we get a palindrome (2422442242).

The spelling of 1220312021 in words is "one billion, two hundred twenty million, three hundred twelve thousand, twenty-one".