21634801 has 2 divisors, whose sum is σ = 21634802. Its totient is φ = 21634800.

The previous prime is 21634799. The next prime is 21634813. The reversal of 21634801 is 10843612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20034576 + 1600225 = 4476^2 + 1265^2 .

It is a cyclic number.

It is not a de Polignac number, because 21634801 - 2¹ = 21634799 is a prime.

It is a super-2 number, since 2×21634801² = 936129228619202, which contains 22 as substring.

Together with 21634799, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21634871) 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, 10817400 + 10817401.

It is an arithmetic number, because the mean of its divisors is an integer number (10817401).

Almost surely, 2^21634801 is an apocalyptic number.

It is an amenable number.

21634801 is a deficient number, since it is larger than the sum of its proper divisors (1).

21634801 is an equidigital number, since it uses as much as digits as its factorization.

21634801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 21634801 is about 4651.3225001068. The cubic root of 21634801 is about 278.6448163681.

The spelling of 21634801 in words is "twenty-one million, six hundred thirty-four thousand, eight hundred one".