31220021011 has 4 divisors (see below), whose sum is σ = 31236025024. Its totient is φ = 31204017000.

The previous prime is 31220020969. The next prime is 31220021051. The reversal of 31220021011 is 11012002213.

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

It is a cyclic number.

It is not a de Polignac number, because 31220021011 - 2⁷ = 31220020883 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31220020982 and 31220021000.

It is not an unprimeable number, because it can be changed into a prime (31220021051) 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, 7999080 + ... + 8002981.

It is an arithmetic number, because the mean of its divisors is an integer number (7809006256).

Almost surely, 2^31220021011 is an apocalyptic number.

31220021011 is a deficient number, since it is larger than the sum of its proper divisors (16004013).

31220021011 is a wasteful number, since it uses less digits than its factorization.

31220021011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16004012.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 31220021011 its reverse (11012002213), we get a palindrome (42232023224).

The spelling of 31220021011 in words is "thirty-one billion, two hundred twenty million, twenty-one thousand, eleven".