21231472 has 10 divisors (see below), whose sum is σ = 41136008. Its totient is φ = 10615728.

The previous prime is 21231449. The next prime is 21231473. The reversal of 21231472 is 27413212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 663468 + ... + 663499.

Almost surely, 2^21231472 is an apocalyptic number.

It is an amenable number.

21231472 is a deficient number, since it is larger than the sum of its proper divisors (19904536).

21231472 is a wasteful number, since it uses less digits than its factorization.

21231472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1326975 (or 1326969 counting only the distinct ones).

The product of its digits is 672, while the sum is 22.

The square root of 21231472 is about 4607.7621466391. The cubic root of 21231472 is about 276.9023884196.

Adding to 21231472 its reverse (27413212), we get a palindrome (48644684).

It can be divided in two parts, 212 and 31472, that added together give a square (31684 = 178²).

The spelling of 21231472 in words is "twenty-one million, two hundred thirty-one thousand, four hundred seventy-two".