21125477 has 8 divisors (see below), whose sum is σ = 22755840. Its totient is φ = 19554480.

The previous prime is 21125471. The next prime is 21125491. The reversal of 21125477 is 77452112.

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

It is a cyclic number.

It is not a de Polignac number, because 21125477 - 2¹² = 21121381 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 (21125471) 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, 14102 + ... + 15527.

It is an arithmetic number, because the mean of its divisors is an integer number (2844480).

Almost surely, 2^21125477 is an apocalyptic number.

It is an amenable number.

21125477 is a deficient number, since it is larger than the sum of its proper divisors (1630363).

21125477 is a wasteful number, since it uses less digits than its factorization.

21125477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29683.

The product of its digits is 3920, while the sum is 29.

The square root of 21125477 is about 4596.2459681788. The cubic root of 21125477 is about 276.4408213196.

Adding to 21125477 its reverse (77452112), we get a palindrome (98577589).

The spelling of 21125477 in words is "twenty-one million, one hundred twenty-five thousand, four hundred seventy-seven".