31209472 has 72 divisors (see below), whose sum is σ = 72825480. Its totient is φ = 13332480.

The previous prime is 31209449. The next prime is 31209499. The reversal of 31209472 is 27490213.

It is a super-2 number, since 2×31209472² = 1948062285037568, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 31209472.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 100197 + ... + 100507.

It is an arithmetic number, because the mean of its divisors is an integer number (1011465).

Almost surely, 2^31209472 is an apocalyptic number.

31209472 is a gapful number since it is divisible by the number (32) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31209472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36412740).

31209472 is an abundant number, since it is smaller than the sum of its proper divisors (41616008).

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

31209472 is an equidigital number, since it uses as much as digits as its factorization.

31209472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347 (or 320 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 31209472 is about 5586.5438331763. The cubic root of 31209472 is about 314.8440380196.

Adding to 31209472 its reverse (27490213), we get a palindrome (58699685).

The spelling of 31209472 in words is "thirty-one million, two hundred nine thousand, four hundred seventy-two".