31221971 has 8 divisors (see below), whose sum is σ = 35541504. Its totient is φ = 27149320.

The previous prime is 31221961. The next prime is 31221977. The reversal of 31221971 is 17912213.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31221971 - 2¹⁸ = 30959827 is a prime.

It is a super-2 number, since 2×31221971² = 1949622946249682, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31221971.

It is not an unprimeable number, because it can be changed into a prime (31221977) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61451 + ... + 61956.

It is an arithmetic number, because the mean of its divisors is an integer number (4442688).

Almost surely, 2^31221971 is an apocalyptic number.

31221971 is a deficient number, since it is larger than the sum of its proper divisors (4319533).

31221971 is a wasteful number, since it uses less digits than its factorization.

31221971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123441.

The product of its digits is 756, while the sum is 26.

The square root of 31221971 is about 5587.6623913762. The cubic root of 31221971 is about 314.8860627657.

The spelling of 31221971 in words is "thirty-one million, two hundred twenty-one thousand, nine hundred seventy-one".