1520661 has 4 divisors (see below), whose sum is σ = 2027552. Its totient is φ = 1013772.

The previous prime is 1520653. The next prime is 1520681. The reversal of 1520661 is 1660251.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1660251 = 3 ⋅553417.

It is not a de Polignac number, because 1520661 - 2³ = 1520653 is a prime.

It is a D-number.

It is a Duffinian number.

1520661 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1520611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 253441 + ... + 253446.

It is an arithmetic number, because the mean of its divisors is an integer number (506888).

2^1520661 is an apocalyptic number.

It is an amenable number.

1520661 is a deficient number, since it is larger than the sum of its proper divisors (506891).

1520661 is an equidigital number, since it uses as much as digits as its factorization.

1520661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506890.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 1520661 is about 1233.1508423547. The cubic root of 1520661 is about 114.9946059222.

The spelling of 1520661 in words is "one million, five hundred twenty thousand, six hundred sixty-one".