21853961 has 2 divisors, whose sum is σ = 21853962. Its totient is φ = 21853960.

The previous prime is 21853927. The next prime is 21853987. The reversal of 21853961 is 16935812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11095561 + 10758400 = 3331^2 + 3280^2 .

It is a cyclic number.

It is not a de Polignac number, because 21853961 - 2¹⁴ = 21837577 is a prime.

It is a super-2 number, since 2×21853961² = 955191222779042, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21853561) 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, 10926980 + 10926981.

It is an arithmetic number, because the mean of its divisors is an integer number (10926981).

Almost surely, 2^21853961 is an apocalyptic number.

It is an amenable number.

21853961 is a deficient number, since it is larger than the sum of its proper divisors (1).

21853961 is an equidigital number, since it uses as much as digits as its factorization.

21853961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 35.

The square root of 21853961 is about 4674.8220286980. The cubic root of 21853961 is about 279.5825454395.

The spelling of 21853961 in words is "twenty-one million, eight hundred fifty-three thousand, nine hundred sixty-one".