21953777 has 2 divisors, whose sum is σ = 21953778. Its totient is φ = 21953776.

The previous prime is 21953741. The next prime is 21953791. The reversal of 21953777 is 77735912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20214016 + 1739761 = 4496^2 + 1319^2 .

It is a cyclic number.

It is not a de Polignac number, because 21953777 - 2¹⁴ = 21937393 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21953677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10976888 + 10976889.

It is an arithmetic number, because the mean of its divisors is an integer number (10976889).

Almost surely, 2^21953777 is an apocalyptic number.

It is an amenable number.

21953777 is a deficient number, since it is larger than the sum of its proper divisors (1).

21953777 is an equidigital number, since it uses as much as digits as its factorization.

21953777 is an evil number, because the sum of its binary digits is even.

The product of its digits is 92610, while the sum is 41.

The square root of 21953777 is about 4685.4857805781. The cubic root of 21953777 is about 280.0075550683.

The spelling of 21953777 in words is "twenty-one million, nine hundred fifty-three thousand, seven hundred seventy-seven".