2149661 has 2 divisors, whose sum is σ = 2149662. Its totient is φ = 2149660.

The previous prime is 2149621. The next prime is 2149681. The reversal of 2149661 is 1669412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1651225 + 498436 = 1285^2 + 706^2 .

It is a cyclic number.

It is not a de Polignac number, because 2149661 - 2¹⁴ = 2133277 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2149621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1074830 + 1074831.

It is an arithmetic number, because the mean of its divisors is an integer number (1074831).

2^2149661 is an apocalyptic number.

It is an amenable number.

2149661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2149661 is an equidigital number, since it uses as much as digits as its factorization.

2149661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 29.

The square root of 2149661 is about 1466.1722272639. The cubic root of 2149661 is about 129.0595042269.

Subtracting from 2149661 its reverse (1669412), we obtain a square (480249 = 693²).

The spelling of 2149661 in words is "two million, one hundred forty-nine thousand, six hundred sixty-one".