31221537106 has 4 divisors (see below), whose sum is σ = 46832305662. Its totient is φ = 15610768552.

The previous prime is 31221537103. The next prime is 31221537121. The reversal of 31221537106 is 60173512213.

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 only one way, i.e., 17906454225 + 13315082881 = 133815^2 + 115391^2 .

It is a super-2 number, since 2×31221537106² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (31221537103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7805384275 + ... + 7805384278.

Almost surely, 2^31221537106 is an apocalyptic number.

31221537106 is a deficient number, since it is larger than the sum of its proper divisors (15610768556).

31221537106 is a wasteful number, since it uses less digits than its factorization.

31221537106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15610768555.

The product of its (nonzero) digits is 7560, while the sum is 31.

The spelling of 31221537106 in words is "thirty-one billion, two hundred twenty-one million, five hundred thirty-seven thousand, one hundred six".