20742291 has 16 divisors (see below), whose sum is σ = 30825600. Its totient is φ = 13784904.

The previous prime is 20742247. The next prime is 20742299. The reversal of 20742291 is 19224702.

It is not a de Polignac number, because 20742291 - 2⁹ = 20741779 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (20742299) 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, 9220 + ... + 11246.

It is an arithmetic number, because the mean of its divisors is an integer number (1926600).

Almost surely, 2^20742291 is an apocalyptic number.

20742291 is a deficient number, since it is larger than the sum of its proper divisors (10083309).

20742291 is a wasteful number, since it uses less digits than its factorization.

20742291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2415 (or 2409 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 20742291 is about 4554.3705382852. The cubic root of 20742291 is about 274.7591985722.

Adding to 20742291 its reverse (19224702), we get a palindrome (39966993).

The spelling of 20742291 in words is "twenty million, seven hundred forty-two thousand, two hundred ninety-one".