21455461 has 2 divisors, whose sum is σ = 21455462. Its totient is φ = 21455460.

The previous prime is 21455459. The next prime is 21455491. The reversal of 21455461 is 16455412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14062500 + 7392961 = 3750^2 + 2719^2 .

It is a cyclic number.

It is not a de Polignac number, because 21455461 - 2¹ = 21455459 is a prime.

Together with 21455459, 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 (21455431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10727730 + 10727731.

It is an arithmetic number, because the mean of its divisors is an integer number (10727731).

Almost surely, 2^21455461 is an apocalyptic number.

It is an amenable number.

21455461 is a deficient number, since it is larger than the sum of its proper divisors (1).

21455461 is an equidigital number, since it uses as much as digits as its factorization.

21455461 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4800, while the sum is 28.

The square root of 21455461 is about 4632.0039939534. The cubic root of 21455461 is about 277.8727442344.

The spelling of 21455461 in words is "twenty-one million, four hundred fifty-five thousand, four hundred sixty-one".