21628477 has 8 divisors (see below), whose sum is σ = 23442776. Its totient is φ = 19835712.

The previous prime is 21628469. The next prime is 21628501. The reversal of 21628477 is 77482612.

It can be written as a sum of positive squares in 4 ways, for example, as 962361 + 20666116 = 981^2 + 4546^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21628477 - 2³ = 21628469 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 (21628417) 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 in 7 ways as a sum of consecutive naturals, for example, 3258 + ... + 7339.

It is an arithmetic number, because the mean of its divisors is an integer number (2930347).

Almost surely, 2^21628477 is an apocalyptic number.

It is an amenable number.

21628477 is a deficient number, since it is larger than the sum of its proper divisors (1814299).

21628477 is a wasteful number, since it uses less digits than its factorization.

21628477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10767.

The product of its digits is 37632, while the sum is 37.

The square root of 21628477 is about 4650.6426437644. The cubic root of 21628477 is about 278.6176637951.

The spelling of 21628477 in words is "twenty-one million, six hundred twenty-eight thousand, four hundred seventy-seven".