31729428 has 24 divisors (see below), whose sum is σ = 82261760. Its totient is φ = 10576440.

The previous prime is 31729409. The next prime is 31729447. The reversal of 31729428 is 82492713.

It is an interprime number because it is at equal distance from previous prime (31729409) and next prime (31729447).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 31729392 and 31729401.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 146788 + ... + 147003.

Almost surely, 2^31729428 is an apocalyptic number.

It is an amenable number.

31729428 is an abundant number, since it is smaller than the sum of its proper divisors (50532332).

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

31729428 is a wasteful number, since it uses less digits than its factorization.

31729428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 293804 (or 293796 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 31729428 is about 5632.8880691880. Note that the first 3 decimals coincide. The cubic root of 31729428 is about 316.5828717651.

The spelling of 31729428 in words is "thirty-one million, seven hundred twenty-nine thousand, four hundred twenty-eight".