21277471 has 4 divisors (see below), whose sum is σ = 21626344. Its totient is φ = 20928600.

The previous prime is 21277469. The next prime is 21277519. The reversal of 21277471 is 17477212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21277471 - 2¹ = 21277469 is a prime.

It is a super-3 number, since 3×21277471³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21277411) 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 in 3 ways as a sum of consecutive naturals, for example, 174345 + ... + 174466.

It is an arithmetic number, because the mean of its divisors is an integer number (5406586).

Almost surely, 2^21277471 is an apocalyptic number.

21277471 is a deficient number, since it is larger than the sum of its proper divisors (348873).

21277471 is an equidigital number, since it uses as much as digits as its factorization.

21277471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 348872.

The product of its digits is 5488, while the sum is 31.

The square root of 21277471 is about 4612.7509145845. The cubic root of 21277471 is about 277.1022182667.

The spelling of 21277471 in words is "twenty-one million, two hundred seventy-seven thousand, four hundred seventy-one".