21418751 has 2 divisors, whose sum is σ = 21418752. Its totient is φ = 21418750.

The previous prime is 21418741. The next prime is 21418753. The reversal of 21418751 is 15781412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21418751 - 2¹⁰ = 21417727 is a prime.

Together with 21418753, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21418753) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10709375 + 10709376.

It is an arithmetic number, because the mean of its divisors is an integer number (10709376).

Almost surely, 2^21418751 is an apocalyptic number.

21418751 is a deficient number, since it is larger than the sum of its proper divisors (1).

21418751 is an equidigital number, since it uses as much as digits as its factorization.

21418751 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2240, while the sum is 29.

The square root of 21418751 is about 4628.0396497869. The cubic root of 21418751 is about 277.7141749431.

The spelling of 21418751 in words is "twenty-one million, four hundred eighteen thousand, seven hundred fifty-one".