2147661 has 16 divisors (see below), whose sum is σ = 3369600. Its totient is φ = 1347264.

The previous prime is 2147657. The next prime is 2147693. The reversal of 2147661 is 1667412.

It is not a de Polignac number, because 2147661 - 2² = 2147657 is a prime.

It is a super-2 number, since 2×2147661² = 9224895541842, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2147611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1881 + ... + 2798.

It is an arithmetic number, because the mean of its divisors is an integer number (210600).

2^2147661 is an apocalyptic number.

It is an amenable number.

2147661 is a deficient number, since it is larger than the sum of its proper divisors (1221939).

2147661 is a wasteful number, since it uses less digits than its factorization.

2147661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4705 (or 4699 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 2147661 is about 1465.4900204369. The cubic root of 2147661 is about 129.0194670459.

Subtracting from 2147661 its reverse (1667412), we obtain a square (480249 = 693²).

It can be divided in two parts, 214 and 7661, that added together give a triangular number (7875 = T₁₂₅).

The spelling of 2147661 in words is "two million, one hundred forty-seven thousand, six hundred sixty-one".