20172047 has 16 divisors (see below), whose sum is σ = 24572160. Its totient is φ = 16165248.

The previous prime is 20172037. The next prime is 20172073. The reversal of 20172047 is 74027102.

It is a cyclic number.

It is not a de Polignac number, because 20172047 - 2¹² = 20167951 is a prime.

It is a super-4 number, since 4×20172047⁴ (a number of 30 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20172007) 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, 20828 + ... + 21774.

It is an arithmetic number, because the mean of its divisors is an integer number (1535760).

Almost surely, 2^20172047 is an apocalyptic number.

20172047 is a deficient number, since it is larger than the sum of its proper divisors (4400113).

20172047 is a wasteful number, since it uses less digits than its factorization.

20172047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1150.

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 20172047 is about 4491.3302038483. The cubic root of 20172047 is about 272.2178860771.

Adding to 20172047 its reverse (74027102), we get a palindrome (94199149).

The spelling of 20172047 in words is "twenty million, one hundred seventy-two thousand, forty-seven".