20151697 has 4 divisors (see below), whose sum is σ = 20235556. Its totient is φ = 20067840.

The previous prime is 20151683. The next prime is 20151701. The reversal of 20151697 is 79615102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15062161 + 5089536 = 3881^2 + 2256^2 .

It is a cyclic number.

It is not a de Polignac number, because 20151697 - 2¹⁹ = 19627409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20151617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41568 + ... + 42049.

It is an arithmetic number, because the mean of its divisors is an integer number (5058889).

Almost surely, 2^20151697 is an apocalyptic number.

It is an amenable number.

20151697 is a deficient number, since it is larger than the sum of its proper divisors (83859).

20151697 is an equidigital number, since it uses as much as digits as its factorization.

20151697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83858.

The product of its (nonzero) digits is 3780, while the sum is 31.

The square root of 20151697 is about 4489.0641563693. The cubic root of 20151697 is about 272.1263155016.

Adding to 20151697 its reverse (79615102), we get a palindrome (99766799).

The spelling of 20151697 in words is "twenty million, one hundred fifty-one thousand, six hundred ninety-seven".