1540661 has 2 divisors, whose sum is σ = 1540662. Its totient is φ = 1540660.

The previous prime is 1540639. The next prime is 1540673. The reversal of 1540661 is 1660451.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1168561 + 372100 = 1081^2 + 610^2 .

It is a cyclic number.

It is not a de Polignac number, because 1540661 - 2¹⁴ = 1524277 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 (1540621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 770330 + 770331.

It is an arithmetic number, because the mean of its divisors is an integer number (770331).

2^1540661 is an apocalyptic number.

It is an amenable number.

1540661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1540661 is an equidigital number, since it uses as much as digits as its factorization.

1540661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 1540661 is about 1241.2336605168. The cubic root of 1540661 is about 115.4965548094.

The spelling of 1540661 in words is "one million, five hundred forty thousand, six hundred sixty-one".