21116567 has 4 divisors (see below), whose sum is σ = 22358736. Its totient is φ = 19874400.

The previous prime is 21116561. The next prime is 21116587. The reversal of 21116567 is 76561112.

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

It is a cyclic number.

It is not a de Polignac number, because 21116567 - 2⁶ = 21116503 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21116561) 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, 621059 + ... + 621092.

It is an arithmetic number, because the mean of its divisors is an integer number (5589684).

Almost surely, 2^21116567 is an apocalyptic number.

21116567 is a deficient number, since it is larger than the sum of its proper divisors (1242169).

21116567 is a wasteful number, since it uses less digits than its factorization.

21116567 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1242168.

The product of its digits is 2520, while the sum is 29.

The square root of 21116567 is about 4595.2765966806. The cubic root of 21116567 is about 276.4019514426.

Adding to 21116567 its reverse (76561112), we get a palindrome (97677679).

The spelling of 21116567 in words is "twenty-one million, one hundred sixteen thousand, five hundred sixty-seven".