21899777 has 2 divisors, whose sum is σ = 21899778. Its totient is φ = 21899776.

The previous prime is 21899743. The next prime is 21899783. The reversal of 21899777 is 77799812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21520321 + 379456 = 4639^2 + 616^2 .

It is a cyclic number.

It is not a de Polignac number, because 21899777 - 2¹⁰ = 21898753 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21899707) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10949888 + 10949889.

It is an arithmetic number, because the mean of its divisors is an integer number (10949889).

Almost surely, 2^21899777 is an apocalyptic number.

It is an amenable number.

21899777 is a deficient number, since it is larger than the sum of its proper divisors (1).

21899777 is an equidigital number, since it uses as much as digits as its factorization.

21899777 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 444528, while the sum is 50.

The square root of 21899777 is about 4679.7197565666. The cubic root of 21899777 is about 279.7777871300. Note that the first 4 decimals are identical.

The spelling of 21899777 in words is "twenty-one million, eight hundred ninety-nine thousand, seven hundred seventy-seven".