21051472 has 20 divisors (see below), whose sum is σ = 43925140. Its totient is φ = 9715968.

The previous prime is 21051461. The next prime is 21051473. The reversal of 21051472 is 27415012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 3779136 + 17272336 = 1944^2 + 4156^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051473) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50397 + ... + 50812.

It is an arithmetic number, because the mean of its divisors is an integer number (2196257).

Almost surely, 2^21051472 is an apocalyptic number.

It is an amenable number.

21051472 is an abundant number, since it is smaller than the sum of its proper divisors (22873668).

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

21051472 is a wasteful number, since it uses less digits than its factorization.

21051472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101230 (or 101224 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 21051472 is about 4588.1883134850. The cubic root of 21051472 is about 276.1176422106.

Adding to 21051472 its reverse (27415012), we get a palindrome (48466484).

The spelling of 21051472 in words is "twenty-one million, fifty-one thousand, four hundred seventy-two".