20247551 has 4 divisors (see below), whose sum is σ = 20260104. Its totient is φ = 20235000.

The previous prime is 20247541. The next prime is 20247593. The reversal of 20247551 is 15574202.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20247551 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20247551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20247541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3425 + ... + 7226.

It is an arithmetic number, because the mean of its divisors is an integer number (5065026).

Almost surely, 2^20247551 is an apocalyptic number.

20247551 is a deficient number, since it is larger than the sum of its proper divisors (12553).

20247551 is a wasteful number, since it uses less digits than its factorization.

20247551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12552.

The product of its (nonzero) digits is 2800, while the sum is 26.

The square root of 20247551 is about 4499.7278806612. The cubic root of 20247551 is about 272.5571005106.

The spelling of 20247551 in words is "twenty million, two hundred forty-seven thousand, five hundred fifty-one".