31221021042 has 24 divisors (see below), whose sum is σ = 68501821440. Its totient is φ = 10275272280.

The previous prime is 31221020977. The next prime is 31221021053. The reversal of 31221021042 is 24012012213.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10976434 + ... + 10979277.

It is an arithmetic number, because the mean of its divisors is an integer number (2854242560).

Almost surely, 2^31221021042 is an apocalyptic number.

31221021042 is an abundant number, since it is smaller than the sum of its proper divisors (37280800398).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31221021042 is a wasteful number, since it uses less digits than its factorization.

31221021042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21955798 (or 21955795 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 31221021042 its reverse (24012012213), we get a palindrome (55233033255).

The spelling of 31221021042 in words is "thirty-one billion, two hundred twenty-one million, twenty-one thousand, forty-two".