2991861 has 12 divisors (see below), whose sum is σ = 4337580. Its totient is φ = 1987200.

The previous prime is 2991853. The next prime is 2991871. The reversal of 2991861 is 1681992.

It can be written as a sum of positive squares in 2 ways, for example, as 2528100 + 463761 = 1590^2 + 681^2 .

It is not a de Polignac number, because 2991861 - 2³ = 2991853 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2991871) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3195 + ... + 4023.

It is an arithmetic number, because the mean of its divisors is an integer number (361465).

2^2991861 is an apocalyptic number.

It is an amenable number.

2991861 is a deficient number, since it is larger than the sum of its proper divisors (1345719).

2991861 is a wasteful number, since it uses less digits than its factorization.

2991861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1236 (or 1233 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 2991861 is about 1729.6996849164. The cubic root of 2991861 is about 144.0944114666.

The spelling of 2991861 in words is "two million, nine hundred ninety-one thousand, eight hundred sixty-one".