21899047 has 2 divisors, whose sum is σ = 21899048. Its totient is φ = 21899046.

The previous prime is 21899023. The next prime is 21899063. The reversal of 21899047 is 74099812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21899047 - 2¹¹ = 21896999 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21899447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10949523 + 10949524.

It is an arithmetic number, because the mean of its divisors is an integer number (10949524).

Almost surely, 2^21899047 is an apocalyptic number.

21899047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21899047 is an equidigital number, since it uses as much as digits as its factorization.

21899047 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 21899047 is about 4679.6417597932. The cubic root of 21899047 is about 279.7746784218.

It can be divided in two parts, 2189 and 9047, that added together give a square (11236 = 106²).

The spelling of 21899047 in words is "twenty-one million, eight hundred ninety-nine thousand, forty-seven".