21418807 has 2 divisors, whose sum is σ = 21418808. Its totient is φ = 21418806.

The previous prime is 21418801. The next prime is 21418823. The reversal of 21418807 is 70881412.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21418807 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21418801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10709403 + 10709404.

It is an arithmetic number, because the mean of its divisors is an integer number (10709404).

Almost surely, 2^21418807 is an apocalyptic number.

21418807 is a deficient number, since it is larger than the sum of its proper divisors (1).

21418807 is an equidigital number, since it uses as much as digits as its factorization.

21418807 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3584, while the sum is 31.

The square root of 21418807 is about 4628.0456998608. The cubic root of 21418807 is about 277.7144169738.

The spelling of 21418807 in words is "twenty-one million, four hundred eighteen thousand, eight hundred seven".