31004021 has 4 divisors (see below), whose sum is σ = 31015500. Its totient is φ = 30992544.

The previous prime is 31004011. The next prime is 31004027. The reversal of 31004021 is 12040013.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 8059921 + 22944100 = 2839^2 + 4790^2 .

It is a cyclic number.

It is not a de Polignac number, because 31004021 - 2⁶ = 31003957 is a prime.

It is a super-2 number, since 2×31004021² = 1922498636336882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31003993 and 31004011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31004027) 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, 785 + ... + 7913.

It is an arithmetic number, because the mean of its divisors is an integer number (7753875).

Almost surely, 2^31004021 is an apocalyptic number.

It is an amenable number.

31004021 is a deficient number, since it is larger than the sum of its proper divisors (11479).

31004021 is an equidigital number, since it uses as much as digits as its factorization.

31004021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11478.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 31004021 is about 5568.1254475811. The cubic root of 31004021 is about 314.1516469010.

Adding to 31004021 its reverse (12040013), we get a palindrome (43044034).

The spelling of 31004021 in words is "thirty-one million, four thousand, twenty-one".