20421660266355 has 32 divisors (see below), whose sum is σ = 36417573734400. Its totient is φ = 9711352991232.

The previous prime is 20421660266323. The next prime is 20421660266383. The reversal of 20421660266355 is 55366206612402.

It is not a de Polignac number, because 20421660266355 - 2⁵ = 20421660266323 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2107493635 + ... + 2107503324.

It is an arithmetic number, because the mean of its divisors is an integer number (1138049179200).

Almost surely, 2^{20421660266355} is an apocalyptic number.

20421660266355 is a deficient number, since it is larger than the sum of its proper divisors (15995913468045).

20421660266355 is a wasteful number, since it uses less digits than its factorization.

20421660266355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4214997003.

The product of its (nonzero) digits is 3110400, while the sum is 48.

Adding to 20421660266355 its reverse (55366206612402), we get a palindrome (75787866878757).

The spelling of 20421660266355 in words is "twenty trillion, four hundred twenty-one billion, six hundred sixty million, two hundred sixty-six thousand, three hundred fifty-five".