20667521 has 8 divisors (see below), whose sum is σ = 23777664. Its totient is φ = 17596800.

The previous prime is 20667511. The next prime is 20667527. The reversal of 20667521 is 12576602.

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 20667521 - 2⁶ = 20667457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20667527) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8720 + ... + 10833.

It is an arithmetic number, because the mean of its divisors is an integer number (2972208).

Almost surely, 2^20667521 is an apocalyptic number.

It is an amenable number.

20667521 is a deficient number, since it is larger than the sum of its proper divisors (3110143).

20667521 is a wasteful number, since it uses less digits than its factorization.

20667521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19711.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 20667521 is about 4546.1545288298. The cubic root of 20667521 is about 274.4286584276.

The spelling of 20667521 in words is "twenty million, six hundred sixty-seven thousand, five hundred twenty-one".