21321477 has 24 divisors (see below), whose sum is σ = 32920160. Its totient is φ = 13258080.

The previous prime is 21321449. The next prime is 21321481. The reversal of 21321477 is 77412312.

It is a happy number.

It is not a de Polignac number, because 21321477 - 2²⁴ = 4544261 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21321477.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321407) 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 23 ways as a sum of consecutive naturals, for example, 10527 + ... + 12387.

Almost surely, 2^21321477 is an apocalyptic number.

It is an amenable number.

21321477 is a deficient number, since it is larger than the sum of its proper divisors (11598683).

21321477 is a wasteful number, since it uses less digits than its factorization.

21321477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1953 (or 1950 counting only the distinct ones).

The product of its digits is 2352, while the sum is 27.

The square root of 21321477 is about 4617.5184894053. The cubic root of 21321477 is about 277.2931207041.

Adding to 21321477 its reverse (77412312), we get a palindrome (98733789).

The spelling of 21321477 in words is "twenty-one million, three hundred twenty-one thousand, four hundred seventy-seven".