20178200661 has 16 divisors (see below), whose sum is σ = 26963698560. Its totient is φ = 13422447360.

The previous prime is 20178200533. The next prime is 20178200729. The reversal of 20178200661 is 16600287102.

It is not a de Polignac number, because 20178200661 - 2⁷ = 20178200533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20178204661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5133745 + ... + 5137673.

It is an arithmetic number, because the mean of its divisors is an integer number (1685231160).

Almost surely, 2^20178200661 is an apocalyptic number.

It is an amenable number.

20178200661 is a deficient number, since it is larger than the sum of its proper divisors (6785497899).

20178200661 is a wasteful number, since it uses less digits than its factorization.

20178200661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7276.

The product of its (nonzero) digits is 8064, while the sum is 33.

Adding to 20178200661 its reverse (16600287102), we get a palindrome (36778487763).

The spelling of 20178200661 in words is "twenty billion, one hundred seventy-eight million, two hundred thousand, six hundred sixty-one".