21086207 has 4 divisors (see below), whose sum is σ = 21095760. Its totient is φ = 21076656.

The previous prime is 21086203. The next prime is 21086227. The reversal of 21086207 is 70268012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21086207 - 2² = 21086203 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 (21086201) 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, 419 + ... + 6507.

It is an arithmetic number, because the mean of its divisors is an integer number (5273940).

Almost surely, 2^21086207 is an apocalyptic number.

21086207 is a deficient number, since it is larger than the sum of its proper divisors (9553).

21086207 is an equidigital number, since it uses as much as digits as its factorization.

21086207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9552.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 21086207 is about 4591.9720164653. The cubic root of 21086207 is about 276.2694237757.

The spelling of 21086207 in words is "twenty-one million, eighty-six thousand, two hundred seven".