21313477 has 4 divisors (see below), whose sum is σ = 21333676. Its totient is φ = 21293280.

The previous prime is 21313469. The next prime is 21313483. The reversal of 21313477 is 77431312.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2076481 + 19236996 = 1441^2 + 4386^2 .

It is a cyclic number.

It is not a de Polignac number, because 21313477 - 2³ = 21313469 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21313447) 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, 8424 + ... + 10657.

It is an arithmetic number, because the mean of its divisors is an integer number (5333419).

Almost surely, 2^21313477 is an apocalyptic number.

It is an amenable number.

21313477 is a deficient number, since it is larger than the sum of its proper divisors (20199).

21313477 is a wasteful number, since it uses less digits than its factorization.

21313477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20198.

The product of its digits is 3528, while the sum is 28.

The square root of 21313477 is about 4616.6521419747. The cubic root of 21313477 is about 277.2584354511.

Adding to 21313477 its reverse (77431312), we get a palindrome (98744789).

The spelling of 21313477 in words is "twenty-one million, three hundred thirteen thousand, four hundred seventy-seven".