2166156603261 has 16 divisors (see below), whose sum is σ = 3667566736000. Its totient is φ = 1237803773184.

The previous prime is 2166156603253. The next prime is 2166156603283. The reversal of 2166156603261 is 1623066516612.

2166156603261 is a `hidden beast` number, since 2 + 1 + 6 + 6 + 15 + 6 + 603 + 26 + 1 = 666.

It is not a de Polignac number, because 2166156603261 - 2³ = 2166156603253 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166156603251) 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, 5730572836 + ... + 5730573213.

It is an arithmetic number, because the mean of its divisors is an integer number (229222921000).

Almost surely, 2^{2166156603261} is an apocalyptic number.

2166156603261 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2166156603261 is a deficient number, since it is larger than the sum of its proper divisors (1501410132739).

2166156603261 is a wasteful number, since it uses less digits than its factorization.

2166156603261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11461146065 (or 11461146059 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 45.

The spelling of 2166156603261 in words is "two trillion, one hundred sixty-six billion, one hundred fifty-six million, six hundred three thousand, two hundred sixty-one".