21461357 has 2 divisors, whose sum is σ = 21461358. Its totient is φ = 21461356.

The previous prime is 21461329. The next prime is 21461359. The reversal of 21461357 is 75316412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19061956 + 2399401 = 4366^2 + 1549^2 .

It is a cyclic number.

It is not a de Polignac number, because 21461357 - 2¹⁶ = 21395821 is a prime.

Together with 21461359, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21461359) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10730678 + 10730679.

It is an arithmetic number, because the mean of its divisors is an integer number (10730679).

Almost surely, 2^21461357 is an apocalyptic number.

It is an amenable number.

21461357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21461357 is an equidigital number, since it uses as much as digits as its factorization.

21461357 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5040, while the sum is 29.

The square root of 21461357 is about 4632.6403918284. The cubic root of 21461357 is about 277.8981952163.

Adding to 21461357 its reverse (75316412), we get a palindrome (96777769).

The spelling of 21461357 in words is "twenty-one million, four hundred sixty-one thousand, three hundred fifty-seven".