31402728 has 240 divisors, whose sum is σ = 109248480. Its totient is φ = 8382528.

The previous prime is 31402717. The next prime is 31402747. The reversal of 31402728 is 82720413.

It is a super-2 number, since 2×31402728² = 1972262651683968, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 730275 + ... + 730317.

It is an arithmetic number, because the mean of its divisors is an integer number (455202).

Almost surely, 2^31402728 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 31402728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (54624240).

31402728 is an abundant number, since it is smaller than the sum of its proper divisors (77845752).

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

31402728 is a wasteful number, since it uses less digits than its factorization.

31402728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98 (or 78 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 31402728 is about 5603.8137014001. The cubic root of 31402728 is about 315.4925627159.

The spelling of 31402728 in words is "thirty-one million, four hundred two thousand, seven hundred twenty-eight".