1621201115563 has 4 divisors (see below), whose sum is σ = 1640733659208. Its totient is φ = 1601668571920.

The previous prime is 1621201115509. The next prime is 1621201115591. The reversal of 1621201115563 is 3655111021261.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1621201115563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1621201112563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9766271698 + ... + 9766271863.

It is an arithmetic number, because the mean of its divisors is an integer number (410183414802).

Almost surely, 2^{1621201115563} is an apocalyptic number.

1621201115563 is a deficient number, since it is larger than the sum of its proper divisors (19532543645).

1621201115563 is an equidigital number, since it uses as much as digits as its factorization.

1621201115563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19532543644.

The product of its (nonzero) digits is 10800, while the sum is 34.

The spelling of 1621201115563 in words is "one trillion, six hundred twenty-one billion, two hundred one million, one hundred fifteen thousand, five hundred sixty-three".