2115561 has 8 divisors (see below), whose sum is σ = 3223744. Its totient is φ = 1208880.

The previous prime is 2115539. The next prime is 2115571. The reversal of 2115561 is 1655112.

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

It is not a de Polignac number, because 2115561 - 2⁷ = 2115433 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 100741 = 2115561 / (2 + 1 + 1 + 5 + 5 + 6 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2115511) 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, 50350 + ... + 50391.

It is an arithmetic number, because the mean of its divisors is an integer number (402968).

2^2115561 is an apocalyptic number.

2115561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2115561 is a deficient number, since it is larger than the sum of its proper divisors (1108183).

2115561 is a wasteful number, since it uses less digits than its factorization.

2115561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100751.

The product of its digits is 300, while the sum is 21.

The square root of 2115561 is about 1454.4968202097. The cubic root of 2115561 is about 128.3734414844.

The spelling of 2115561 in words is "two million, one hundred fifteen thousand, five hundred sixty-one".