20247521 has 16 divisors (see below), whose sum is σ = 25420800. Its totient is φ = 15724368.

The previous prime is 20247509. The next prime is 20247523. The reversal of 20247521 is 12574202.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20247521 - 2⁶ = 20247457 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20247523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 251 + ... + 6368.

It is an arithmetic number, because the mean of its divisors is an integer number (1588800).

Almost surely, 2^20247521 is an apocalyptic number.

It is an amenable number.

20247521 is a deficient number, since it is larger than the sum of its proper divisors (5173279).

20247521 is a wasteful number, since it uses less digits than its factorization.

20247521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6668.

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 20247521 is about 4499.7245471251. The cubic root of 20247521 is about 272.5569658982.

The spelling of 20247521 in words is "twenty million, two hundred forty-seven thousand, five hundred twenty-one".