20561555662003 has 8 divisors (see below), whose sum is σ = 20569860864000. Its totient is φ = 20553250895688.

The previous prime is 20561555661979. The next prime is 20561555662009. The reversal of 20561555662003 is 30026655516502.

It is a happy number.

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 20561555662003 - 2²⁹ = 20561018791091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20561555662009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121162950 + ... + 121332532.

It is an arithmetic number, because the mean of its divisors is an integer number (2571232608000).

Almost surely, 2^{20561555662003} is an apocalyptic number.

20561555662003 is a deficient number, since it is larger than the sum of its proper divisors (8305201997).

20561555662003 is a wasteful number, since it uses less digits than its factorization.

20561555662003 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217841.

The product of its (nonzero) digits is 1620000, while the sum is 46.

The spelling of 20561555662003 in words is "twenty trillion, five hundred sixty-one billion, five hundred fifty-five million, six hundred sixty-two thousand, three".