31040221 has 4 divisors (see below), whose sum is σ = 31059072. Its totient is φ = 31021372.

The previous prime is 31040209. The next prime is 31040231. The reversal of 31040221 is 12204013.

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: 12204013 = 1021 ⋅11953.

It is a cyclic number.

It is not a de Polignac number, because 31040221 - 2¹¹ = 31038173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31040201) 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, 6691 + ... + 10336.

It is an arithmetic number, because the mean of its divisors is an integer number (7764768).

Almost surely, 2^31040221 is an apocalyptic number.

It is an amenable number.

31040221 is a deficient number, since it is larger than the sum of its proper divisors (18851).

31040221 is a wasteful number, since it uses less digits than its factorization.

31040221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18850.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 31040221 is about 5571.3751444325. The cubic root of 31040221 is about 314.2738661708.

Adding to 31040221 its reverse (12204013), we get a palindrome (43244234).

The spelling of 31040221 in words is "thirty-one million, forty thousand, two hundred twenty-one".