100812215561 has 4 divisors (see below), whose sum is σ = 105195355392. Its totient is φ = 96429075732.

The previous prime is 100812215557. The next prime is 100812215587. The reversal of 100812215561 is 165512218001.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 165512218001 = 13 ⋅12731709077.

It is a cyclic number.

It is not a de Polignac number, because 100812215561 - 2² = 100812215557 is a prime.

It is not an unprimeable number, because it can be changed into a prime (100812215551) 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 3 ways as a sum of consecutive naturals, for example, 2191569881 + ... + 2191569926.

It is an arithmetic number, because the mean of its divisors is an integer number (26298838848).

Almost surely, 2^100812215561 is an apocalyptic number.

It is an amenable number.

100812215561 is a deficient number, since it is larger than the sum of its proper divisors (4383139831).

100812215561 is an equidigital number, since it uses as much as digits as its factorization.

100812215561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4383139830.

The product of its (nonzero) digits is 4800, while the sum is 32.

The spelling of 100812215561 in words is "one hundred billion, eight hundred twelve million, two hundred fifteen thousand, five hundred sixty-one".