20402191 has 8 divisors (see below), whose sum is σ = 20865600. Its totient is φ = 19941792.

The previous prime is 20402189. The next prime is 20402201. The reversal of 20402191 is 19120402.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20402191 - 2¹ = 20402189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20402131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17946 + ... + 19048.

It is an arithmetic number, because the mean of its divisors is an integer number (2608200).

Almost surely, 2^20402191 is an apocalyptic number.

20402191 is a deficient number, since it is larger than the sum of its proper divisors (463409).

20402191 is a wasteful number, since it uses less digits than its factorization.

20402191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1505.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 20402191 is about 4516.8784575191. The cubic root of 20402191 is about 273.2492234099.

Adding to 20402191 its reverse (19120402), we get a palindrome (39522593).

The spelling of 20402191 in words is "twenty million, four hundred two thousand, one hundred ninety-one".