21463609 has 2 divisors, whose sum is σ = 21463610. Its totient is φ = 21463608.

The previous prime is 21463601. The next prime is 21463613. The reversal of 21463609 is 90636412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11560000 + 9903609 = 3400^2 + 3147^2 .

It is a cyclic number.

It is not a de Polignac number, because 21463609 - 2³ = 21463601 is a prime.

It is a super-2 number, since 2×21463609² = 921373022609762, which contains 22 as substring.

It is equal to p_1357447 and since 21463609 and 1357447 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21463601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10731804 + 10731805.

It is an arithmetic number, because the mean of its divisors is an integer number (10731805).

Almost surely, 2^21463609 is an apocalyptic number.

It is an amenable number.

21463609 is a deficient number, since it is larger than the sum of its proper divisors (1).

21463609 is an equidigital number, since it uses as much as digits as its factorization.

21463609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 21463609 is about 4632.8834433860. The cubic root of 21463609 is about 277.9079150871.

The spelling of 21463609 in words is "twenty-one million, four hundred sixty-three thousand, six hundred nine".