2543661 has 12 divisors (see below), whose sum is σ = 3692988. Its totient is φ = 1687104.

The previous prime is 2543657. The next prime is 2543699. The reversal of 2543661 is 1663452.

It can be written as a sum of positive squares in 2 ways, for example, as 275625 + 2268036 = 525^2 + 1506^2 .

It is not a de Polignac number, because 2543661 - 2² = 2543657 is a prime.

It is a super-2 number, since 2×2543661² = 12940422565842, which contains 22 as substring.

It is a Curzon number.

It is a zygodrome in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2543621) 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, 1491 + ... + 2703.

It is an arithmetic number, because the mean of its divisors is an integer number (307749).

2^2543661 is an apocalyptic number.

It is an amenable number.

2543661 is a deficient number, since it is larger than the sum of its proper divisors (1149327).

2543661 is a wasteful number, since it uses less digits than its factorization.

2543661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1452 (or 1449 counting only the distinct ones).

The product of its digits is 4320, while the sum is 27.

The square root of 2543661 is about 1594.8858893350. The cubic root of 2543661 is about 136.5064200176.

The spelling of 2543661 in words is "two million, five hundred forty-three thousand, six hundred sixty-one".