20615897 has 8 divisors (see below), whose sum is σ = 21486600. Its totient is φ = 19755904.

The previous prime is 20615873. The next prime is 20615909. The reversal of 20615897 is 79851602.

It can be written as a sum of positive squares in 4 ways, for example, as 6635776 + 13980121 = 2576^2 + 3739^2 .

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 20615897 - 2¹⁰ = 20614873 is a prime.

It is a super-2 number, since 2×20615897² = 850030418229218, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20615897.

It is not an unprimeable number, because it can be changed into a prime (20615807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1379 + ... + 6567.

It is an arithmetic number, because the mean of its divisors is an integer number (2685825).

Almost surely, 2^20615897 is an apocalyptic number.

It is an amenable number.

20615897 is a deficient number, since it is larger than the sum of its proper divisors (870703).

20615897 is a wasteful number, since it uses less digits than its factorization.

20615897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5355.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 20615897 is about 4540.4732132235. The cubic root of 20615897 is about 274.1999756691.

It can be divided in two parts, 20615 and 897, that added together give a palindrome (21512).

The spelling of 20615897 in words is "twenty million, six hundred fifteen thousand, eight hundred ninety-seven".