312020021 has 4 divisors (see below), whose sum is σ = 314882700. Its totient is φ = 309157344.

The previous prime is 312020017. The next prime is 312020029. The reversal of 312020021 is 120020213.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 273406225 + 38613796 = 16535^2 + 6214^2 .

It is a cyclic number.

It is not a de Polignac number, because 312020021 - 2² = 312020017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 312019984 and 312020011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (312020029) 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, 1431176 + ... + 1431393.

It is an arithmetic number, because the mean of its divisors is an integer number (78720675).

Almost surely, 2^312020021 is an apocalyptic number.

It is an amenable number.

312020021 is a deficient number, since it is larger than the sum of its proper divisors (2862679).

312020021 is a wasteful number, since it uses less digits than its factorization.

312020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2862678.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 312020021 is about 17664.0884565267. The cubic root of 312020021 is about 678.2567958661.

Adding to 312020021 its reverse (120020213), we get a palindrome (432040234).

The spelling of 312020021 in words is "three hundred twelve million, twenty thousand, twenty-one".