311120021 has 4 divisors (see below), whose sum is σ = 311315232. Its totient is φ = 310924812.

The previous prime is 311119997. The next prime is 311120027. The reversal of 311120021 is 120021113.

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, and also an emirpimes, since its reverse is a distinct semiprime: 120021113 = 3433 ⋅34961.

It is a cyclic number.

It is not a de Polignac number, because 311120021 - 2⁶ = 311119957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 311119984 and 311120011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311120027) 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, 95195 + ... + 98408.

It is an arithmetic number, because the mean of its divisors is an integer number (77828808).

Almost surely, 2^311120021 is an apocalyptic number.

It is an amenable number.

311120021 is a deficient number, since it is larger than the sum of its proper divisors (195211).

311120021 is a wasteful number, since it uses less digits than its factorization.

311120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195210.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 311120021 is about 17638.5946435650. The cubic root of 311120021 is about 677.6040397043.

Adding to 311120021 its reverse (120021113), we get a palindrome (431141134).

It can be divided in two parts, 3111 and 20021, that added together give a palindrome (23132).

The spelling of 311120021 in words is "three hundred eleven million, one hundred twenty thousand, twenty-one".