21343572 has 18 divisors (see below), whose sum is σ = 53951898. Its totient is φ = 7114512.

The previous prime is 21343519. The next prime is 21343579. The reversal of 21343572 is 27534312.

It can be written as a sum of positive squares in only one way, i.e., 15023376 + 6320196 = 3876^2 + 2514^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21343579) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 296403 + ... + 296474.

Almost surely, 2^21343572 is an apocalyptic number.

It is an amenable number.

21343572 is an abundant number, since it is smaller than the sum of its proper divisors (32608326).

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

21343572 is a wasteful number, since it uses less digits than its factorization.

21343572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592887 (or 592882 counting only the distinct ones).

The product of its digits is 5040, while the sum is 27.

The square root of 21343572 is about 4619.9103887413. The cubic root of 21343572 is about 277.3888719875.

Adding to 21343572 its reverse (27534312), we get a palindrome (48877884).

The spelling of 21343572 in words is "twenty-one million, three hundred forty-three thousand, five hundred seventy-two".