3656126666021 has 8 divisors (see below), whose sum is σ = 3692364770424. Its totient is φ = 3619889323200.

The previous prime is 3656126665999. The next prime is 3656126666047. The reversal of 3656126666021 is 1206666216563.

It can be written as a sum of positive squares in 4 ways, for example, as 602352940996 + 3053773725025 = 776114^2 + 1747505^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3656126666021 - 2⁶ = 3656126665957 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 (3656126696021) 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 7 ways as a sum of consecutive naturals, for example, 18555995 + ... + 18751991.

It is an arithmetic number, because the mean of its divisors is an integer number (461545596303).

Almost surely, 2^{3656126666021} is an apocalyptic number.

It is an amenable number.

3656126666021 is a deficient number, since it is larger than the sum of its proper divisors (36238104403).

3656126666021 is a wasteful number, since it uses less digits than its factorization.

3656126666021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380791.

The product of its (nonzero) digits is 2799360, while the sum is 50.

The spelling of 3656126666021 in words is "three trillion, six hundred fifty-six billion, one hundred twenty-six million, six hundred sixty-six thousand, twenty-one".