21440534 has 4 divisors (see below), whose sum is σ = 32160804. Its totient is φ = 10720266.

The previous prime is 21440527. The next prime is 21440537. The reversal of 21440534 is 43504412.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5360132 + ... + 5360135.

It is an arithmetic number, because the mean of its divisors is an integer number (8040201).

Almost surely, 2^21440534 is an apocalyptic number.

21440534 is a deficient number, since it is larger than the sum of its proper divisors (10720270).

21440534 is a wasteful number, since it uses less digits than its factorization.

21440534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10720269.

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 21440534 is about 4630.3924239745. The cubic root of 21440534 is about 277.8082887138.

Adding to 21440534 its reverse (43504412), we get a palindrome (64944946).

The spelling of 21440534 in words is "twenty-one million, four hundred forty thousand, five hundred thirty-four".