20897611 has 4 divisors (see below), whose sum is σ = 23882992. Its totient is φ = 17912232.

The previous prime is 20897609. The next prime is 20897671. The reversal of 20897611 is 11679802.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11679802 = 2 ⋅5839901.

It is a cyclic number.

It is not a de Polignac number, because 20897611 - 2¹ = 20897609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20897671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1492680 + ... + 1492693.

It is an arithmetic number, because the mean of its divisors is an integer number (5970748).

Almost surely, 2^20897611 is an apocalyptic number.

20897611 is a deficient number, since it is larger than the sum of its proper divisors (2985381).

20897611 is an equidigital number, since it uses as much as digits as its factorization.

20897611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2985380.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 20897611 is about 4571.3904886807. The cubic root of 20897611 is about 275.4433004420.

The spelling of 20897611 in words is "twenty million, eight hundred ninety-seven thousand, six hundred eleven".