21962261 has 2 divisors, whose sum is σ = 21962262. Its totient is φ = 21962260.

The previous prime is 21962209. The next prime is 21962267. The reversal of 21962261 is 16226912.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15171025 + 6791236 = 3895^2 + 2606^2 .

It is a cyclic number.

It is not a de Polignac number, because 21962261 - 2⁶ = 21962197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21962267) 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, 10981130 + 10981131.

It is an arithmetic number, because the mean of its divisors is an integer number (10981131).

Almost surely, 2^21962261 is an apocalyptic number.

It is an amenable number.

21962261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21962261 is an equidigital number, since it uses as much as digits as its factorization.

21962261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 29.

The square root of 21962261 is about 4686.3910421560. The cubic root of 21962261 is about 280.0436199050.

The spelling of 21962261 in words is "twenty-one million, nine hundred sixty-two thousand, two hundred sixty-one".