20172642 has 64 divisors (see below), whose sum is σ = 51425280. Its totient is φ = 5135616.

The previous prime is 20172641. The next prime is 20172643. The reversal of 20172642 is 24627102.

It is an interprime number because it is at equal distance from previous prime (20172641) and next prime (20172643).

It is not an unprimeable number, because it can be changed into a prime (20172641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12823 + ... + 14309.

It is an arithmetic number, because the mean of its divisors is an integer number (803520).

Almost surely, 2^20172642 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20172642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25712640).

20172642 is an abundant number, since it is smaller than the sum of its proper divisors (31252638).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20172642 is a wasteful number, since it uses less digits than its factorization.

20172642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1535.

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 20172642 is about 4491.3964420879. The cubic root of 20172642 is about 272.2205625209.

Adding to 20172642 its reverse (24627102), we get a palindrome (44799744).

The spelling of 20172642 in words is "twenty million, one hundred seventy-two thousand, six hundred forty-two".