20472551 has 4 divisors (see below), whose sum is σ = 22333704. Its totient is φ = 18611400.

The previous prime is 20472533. The next prime is 20472559. The reversal of 20472551 is 15527402.

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-20472551 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 20472551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20472559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 930560 + ... + 930581.

It is an arithmetic number, because the mean of its divisors is an integer number (5583426).

Almost surely, 2^20472551 is an apocalyptic number.

20472551 is a deficient number, since it is larger than the sum of its proper divisors (1861153).

20472551 is a wasteful number, since it uses less digits than its factorization.

20472551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1861152.

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

The square root of 20472551 is about 4524.6603187422. The cubic root of 20472551 is about 273.5629765843.

Adding to 20472551 its reverse (15527402), we get a palindrome (35999953).

The spelling of 20472551 in words is "twenty million, four hundred seventy-two thousand, five hundred fifty-one".