20097661 has 4 divisors (see below), whose sum is σ = 20107872. Its totient is φ = 20087452.

The previous prime is 20097643. The next prime is 20097677. The reversal of 20097661 is 16679002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20097661 - 2⁵ = 20097629 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 (20097691) 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, 1111 + ... + 6436.

It is an arithmetic number, because the mean of its divisors is an integer number (5026968).

Almost surely, 2^20097661 is an apocalyptic number.

It is an amenable number.

20097661 is a deficient number, since it is larger than the sum of its proper divisors (10211).

20097661 is an equidigital number, since it uses as much as digits as its factorization.

20097661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10210.

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 20097661 is about 4483.0414898816. The cubic root of 20097661 is about 271.8828656904.

The spelling of 20097661 in words is "twenty million, ninety-seven thousand, six hundred sixty-one".