1500661 has 8 divisors (see below), whose sum is σ = 1550744. Its totient is φ = 1451520.

The previous prime is 1500649. The next prime is 1500691. The reversal of 1500661 is 1660051.

It can be written as a sum of positive squares in 4 ways, for example, as 36 + 1500625 = 6^2 + 1225^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 5-Lehmer number, since φ(1500661) divides (1500661-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 1500661 - 2⁷ = 1500533 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1500691) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4285 + ... + 4621.

It is an arithmetic number, because the mean of its divisors is an integer number (193843).

It is a Poulet number, since it divides 2^1500660-1.

2^1500661 is an apocalyptic number.

It is an amenable number.

1500661 is a deficient number, since it is larger than the sum of its proper divisors (50083).

1500661 is an equidigital number, since it uses as much as digits as its factorization.

1500661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 1500661 is about 1225.0146937894. The cubic root of 1500661 is about 114.4882363664.

The spelling of 1500661 in words is "one million, five hundred thousand, six hundred sixty-one".