21378883 has 2 divisors, whose sum is σ = 21378884. Its totient is φ = 21378882.

The previous prime is 21378817. The next prime is 21378899. The reversal of 21378883 is 38887312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21378883 is a prime.

It is not a weakly prime, because it can be changed into another prime (21378083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10689441 + 10689442.

It is an arithmetic number, because the mean of its divisors is an integer number (10689442).

Almost surely, 2^21378883 is an apocalyptic number.

21378883 is a deficient number, since it is larger than the sum of its proper divisors (1).

21378883 is an equidigital number, since it uses as much as digits as its factorization.

21378883 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64512, while the sum is 40.

The square root of 21378883 is about 4623.7304203424. The cubic root of 21378883 is about 277.5417592649.

The spelling of 21378883 in words is "twenty-one million, three hundred seventy-eight thousand, eight hundred eighty-three".