21541477 has 2 divisors, whose sum is σ = 21541478. Its totient is φ = 21541476.

The previous prime is 21541453. The next prime is 21541493. The reversal of 21541477 is 77414512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19368801 + 2172676 = 4401^2 + 1474^2 .

It is a cyclic number.

It is not a de Polignac number, because 21541477 - 2¹⁹ = 21017189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21541417) 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, 10770738 + 10770739.

It is an arithmetic number, because the mean of its divisors is an integer number (10770739).

Almost surely, 2^21541477 is an apocalyptic number.

It is an amenable number.

21541477 is a deficient number, since it is larger than the sum of its proper divisors (1).

21541477 is an equidigital number, since it uses as much as digits as its factorization.

21541477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7840, while the sum is 31.

The square root of 21541477 is about 4641.2796726765. The cubic root of 21541477 is about 278.2435842761.

Adding to 21541477 its reverse (77414512), we get a palindrome (98955989).

The spelling of 21541477 in words is "twenty-one million, five hundred forty-one thousand, four hundred seventy-seven".