21007479 has 8 divisors (see below), whose sum is σ = 28078192. Its totient is φ = 13970880.

The previous prime is 21007463. The next prime is 21007499. The reversal of 21007479 is 97470012.

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

It is not a de Polignac number, because 21007479 - 2⁴ = 21007463 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 (21007439) 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, 7054 + ... + 9579.

It is an arithmetic number, because the mean of its divisors is an integer number (3509774).

Almost surely, 2^21007479 is an apocalyptic number.

21007479 is a deficient number, since it is larger than the sum of its proper divisors (7070713).

21007479 is a wasteful number, since it uses less digits than its factorization.

21007479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17057.

The product of its (nonzero) digits is 3528, while the sum is 30.

The square root of 21007479 is about 4583.3916481139. The cubic root of 21007479 is about 275.9251661220.

The spelling of 21007479 in words is "twenty-one million, seven thousand, four hundred seventy-nine".