21416537 has 8 divisors (see below), whose sum is σ = 22382976. Its totient is φ = 20471472.

The previous prime is 21416531. The next prime is 21416539. The reversal of 21416537 is 73561412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21416537 - 2⁸ = 21416281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21416531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3278 + ... + 7319.

It is an arithmetic number, because the mean of its divisors is an integer number (2797872).

Almost surely, 2^21416537 is an apocalyptic number.

It is an amenable number.

21416537 is a deficient number, since it is larger than the sum of its proper divisors (966439).

21416537 is a wasteful number, since it uses less digits than its factorization.

21416537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10687.

The product of its digits is 5040, while the sum is 29.

The square root of 21416537 is about 4627.8004494576. The cubic root of 21416537 is about 277.7046057520.

Adding to 21416537 its reverse (73561412), we get a palindrome (94977949).

The spelling of 21416537 in words is "twenty-one million, four hundred sixteen thousand, five hundred thirty-seven".