21534406 has 4 divisors (see below), whose sum is σ = 32301612. Its totient is φ = 10767202.

The previous prime is 21534397. The next prime is 21534421. The reversal of 21534406 is 60443512.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5383600 + ... + 5383603.

It is an arithmetic number, because the mean of its divisors is an integer number (8075403).

Almost surely, 2^21534406 is an apocalyptic number.

21534406 is a deficient number, since it is larger than the sum of its proper divisors (10767206).

21534406 is a wasteful number, since it uses less digits than its factorization.

21534406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10767205.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 21534406 is about 4640.5178590325. The cubic root of 21534406 is about 278.2131364150.

Adding to 21534406 its reverse (60443512), we get a palindrome (81977918).

The spelling of 21534406 in words is "twenty-one million, five hundred thirty-four thousand, four hundred six".