20163251115661 has 4 divisors (see below), whose sum is σ = 20190535624000. Its totient is φ = 20135966607324.

The previous prime is 20163251115647. The next prime is 20163251115703. The reversal of 20163251115661 is 16651115236102.

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.

It is a cyclic number.

It is not a de Polignac number, because 20163251115661 - 2¹¹ = 20163251113613 is a prime.

It is a super-2 number, since 2×20163251115661² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20163251115611) 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, 13642253061 + ... + 13642254538.

It is an arithmetic number, because the mean of its divisors is an integer number (5047633906000).

Almost surely, 2^{20163251115661} is an apocalyptic number.

It is an amenable number.

20163251115661 is a deficient number, since it is larger than the sum of its proper divisors (27284508339).

20163251115661 is an equidigital number, since it uses as much as digits as its factorization.

20163251115661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27284508338.

The product of its (nonzero) digits is 64800, while the sum is 40.

The spelling of 20163251115661 in words is "twenty trillion, one hundred sixty-three billion, two hundred fifty-one million, one hundred fifteen thousand, six hundred sixty-one".