31009428 has 72 divisors (see below), whose sum is σ = 86643648. Its totient is φ = 9301248.

The previous prime is 31009427. The next prime is 31009457. The reversal of 31009428 is 82490013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31009421) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12975 + ... + 15177.

It is an arithmetic number, because the mean of its divisors is an integer number (1203384).

Almost surely, 2^31009428 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31009428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43321824).

31009428 is an abundant number, since it is smaller than the sum of its proper divisors (55634220).

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

31009428 is a wasteful number, since it uses less digits than its factorization.

31009428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2253 (or 2248 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 31009428 is about 5568.6109578601. The cubic root of 31009428 is about 314.1699081798.

The spelling of 31009428 in words is "thirty-one million, nine thousand, four hundred twenty-eight".