31221220219 has 4 divisors (see below), whose sum is σ = 35681394544. Its totient is φ = 26761045896.

The previous prime is 31221220181. The next prime is 31221220237. The reversal of 31221220219 is 91202212213.

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 31221220219 - 2¹³ = 31221212027 is a prime.

It is a super-2 number, since 2×31221220219² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31221220193 and 31221220202.

It is not an unprimeable number, because it can be changed into a prime (31221223219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2230087152 + ... + 2230087165.

It is an arithmetic number, because the mean of its divisors is an integer number (8920348636).

Almost surely, 2^31221220219 is an apocalyptic number.

31221220219 is a deficient number, since it is larger than the sum of its proper divisors (4460174325).

31221220219 is an equidigital number, since it uses as much as digits as its factorization.

31221220219 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4460174324.

The product of its (nonzero) digits is 864, while the sum is 25.

The spelling of 31221220219 in words is "thirty-one billion, two hundred twenty-one million, two hundred twenty thousand, two hundred nineteen".