31425021 has 6 divisors (see below), whose sum is σ = 45391710. Its totient is φ = 20950008.

The previous prime is 31425001. The next prime is 31425029. The reversal of 31425021 is 12052413.

It can be written as a sum of positive squares in only one way, i.e., 30802500 + 622521 = 5550^2 + 789^2 .

It is not a de Polignac number, because 31425021 - 2⁵ = 31424989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31424985 and 31425003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31425029) 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 5 ways as a sum of consecutive naturals, for example, 1745826 + ... + 1745843.

It is an arithmetic number, because the mean of its divisors is an integer number (7565285).

Almost surely, 2^31425021 is an apocalyptic number.

It is an amenable number.

31425021 is a deficient number, since it is larger than the sum of its proper divisors (13966689).

31425021 is a wasteful number, since it uses less digits than its factorization.

31425021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3491675 (or 3491672 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 31425021 is about 5605.8024403291. The cubic root of 31425021 is about 315.5672017943.

Adding to 31425021 its reverse (12052413), we get a palindrome (43477434).

The spelling of 31425021 in words is "thirty-one million, four hundred twenty-five thousand, twenty-one".