20051691 has 8 divisors (see below), whose sum is σ = 29166144. Its totient is φ = 12152520.

The previous prime is 20051683. The next prime is 20051711. The reversal of 20051691 is 19615002.

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

It is not a de Polignac number, because 20051691 - 2³ = 20051683 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20051621) 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, 303781 + ... + 303846.

It is an arithmetic number, because the mean of its divisors is an integer number (3645768).

Almost surely, 2^20051691 is an apocalyptic number.

20051691 is a deficient number, since it is larger than the sum of its proper divisors (9114453).

20051691 is a wasteful number, since it uses less digits than its factorization.

20051691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 607641.

The product of its (nonzero) digits is 540, while the sum is 24.

The square root of 20051691 is about 4477.9114551317. The cubic root of 20051691 is about 271.6754120829.

Adding to 20051691 its reverse (19615002), we get a palindrome (39666693).

The spelling of 20051691 in words is "twenty million, fifty-one thousand, six hundred ninety-one".