21154669 has 2 divisors, whose sum is σ = 21154670. Its totient is φ = 21154668.

The previous prime is 21154631. The next prime is 21154673. The reversal of 21154669 is 96645112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15093225 + 6061444 = 3885^2 + 2462^2 .

It is a cyclic number.

It is not a de Polignac number, because 21154669 - 2⁹ = 21154157 is a prime.

It is a super-2 number, since 2×21154669² = 895040040999122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21152669) 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, 10577334 + 10577335.

It is an arithmetic number, because the mean of its divisors is an integer number (10577335).

Almost surely, 2^21154669 is an apocalyptic number.

It is an amenable number.

21154669 is a deficient number, since it is larger than the sum of its proper divisors (1).

21154669 is an equidigital number, since it uses as much as digits as its factorization.

21154669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 34.

The square root of 21154669 is about 4599.4205069769. The cubic root of 21154669 is about 276.5680949148.

The spelling of 21154669 in words is "twenty-one million, one hundred fifty-four thousand, six hundred sixty-nine".