21746087 has 4 divisors (see below), whose sum is σ = 23723016. Its totient is φ = 19769160.

The previous prime is 21746057. The next prime is 21746099. The reversal of 21746087 is 78064712.

It is a happy number.

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 21746087 - 2²⁰ = 20697511 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 (21746057) 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, 988448 + ... + 988469.

It is an arithmetic number, because the mean of its divisors is an integer number (5930754).

Almost surely, 2^21746087 is an apocalyptic number.

21746087 is a deficient number, since it is larger than the sum of its proper divisors (1976929).

21746087 is a wasteful number, since it uses less digits than its factorization.

21746087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1976928.

The product of its (nonzero) digits is 18816, while the sum is 35.

The square root of 21746087 is about 4663.2699900392. The cubic root of 21746087 is about 279.1217678244.

The spelling of 21746087 in words is "twenty-one million, seven hundred forty-six thousand, eighty-seven".