31220440421 has 4 divisors (see below), whose sum is σ = 31378920012. Its totient is φ = 31061960832.

The previous prime is 31220440409. The next prime is 31220440507. The reversal of 31220440421 is 12404402213.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 29340264100 + 1880176321 = 171290^2 + 43361^2 .

It is a cyclic number.

It is not a de Polignac number, because 31220440421 - 2⁶ = 31220440357 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 (31220440021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79239500 + ... + 79239893.

It is an arithmetic number, because the mean of its divisors is an integer number (7844730003).

Almost surely, 2^31220440421 is an apocalyptic number.

It is an amenable number.

31220440421 is a deficient number, since it is larger than the sum of its proper divisors (158479591).

31220440421 is a wasteful number, since it uses less digits than its factorization.

31220440421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158479590.

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 31220440421 its reverse (12404402213), we get a palindrome (43624842634).

The spelling of 31220440421 in words is "thirty-one billion, two hundred twenty million, four hundred forty thousand, four hundred twenty-one".