21624061 has 2 divisors, whose sum is σ = 21624062. Its totient is φ = 21624060.

The previous prime is 21624059. The next prime is 21624067. The reversal of 21624061 is 16042612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20196036 + 1428025 = 4494^2 + 1195^2 .

It is a cyclic number.

It is not a de Polignac number, because 21624061 - 2¹ = 21624059 is a prime.

Together with 21624059, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21624067) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10812030 + 10812031.

It is an arithmetic number, because the mean of its divisors is an integer number (10812031).

Almost surely, 2^21624061 is an apocalyptic number.

It is an amenable number.

21624061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21624061 is an equidigital number, since it uses as much as digits as its factorization.

21624061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21624061 is about 4650.1678464331. The cubic root of 21624061 is about 278.5987002260.

Adding to 21624061 its reverse (16042612), we get a palindrome (37666673).

The spelling of 21624061 in words is "twenty-one million, six hundred twenty-four thousand, sixty-one".