31321428 has 48 divisors (see below), whose sum is σ = 74941440. Its totient is φ = 10178784.

The previous prime is 31321427. The next prime is 31321441. The reversal of 31321428 is 82412313.

It is a junction number, because it is equal to n+sod(n) for n = 31321398 and 31321407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31321427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 130933 + ... + 131171.

It is an arithmetic number, because the mean of its divisors is an integer number (1561280).

Almost surely, 2^31321428 is an apocalyptic number.

It is an amenable number.

31321428 is an abundant number, since it is smaller than the sum of its proper divisors (43620012).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31321428 is a wasteful number, since it uses less digits than its factorization.

31321428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476 (or 474 counting only the distinct ones).

The product of its digits is 1152, while the sum is 24.

The square root of 31321428 is about 5596.5550117907. Note that the first 3 decimals coincide. The cubic root of 31321428 is about 315.2200629048.

It can be divided in two parts, 3132 and 1428, that added together give a triangular number (4560 = T₉₅).

The spelling of 31321428 in words is "thirty-one million, three hundred twenty-one thousand, four hundred twenty-eight".