21950261 has 2 divisors, whose sum is σ = 21950262. Its totient is φ = 21950260.

The previous prime is 21950239. The next prime is 21950267. The reversal of 21950261 is 16205912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21446161 + 504100 = 4631^2 + 710^2 .

It is a cyclic number.

It is not a de Polignac number, because 21950261 - 2⁶ = 21950197 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21950261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21950267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10975130 + 10975131.

It is an arithmetic number, because the mean of its divisors is an integer number (10975131).

Almost surely, 2^21950261 is an apocalyptic number.

It is an amenable number.

21950261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21950261 is an equidigital number, since it uses as much as digits as its factorization.

21950261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 21950261 is about 4685.1105643304. The cubic root of 21950261 is about 279.9926060973.

The spelling of 21950261 in words is "twenty-one million, nine hundred fifty thousand, two hundred sixty-one".