1520991 has 8 divisors (see below), whose sum is σ = 2253360. Its totient is φ = 1013976.

The previous prime is 1520989. The next prime is 1521011. The reversal of 1520991 is 1990251.

It is a happy number.

It is not a de Polignac number, because 1520991 - 2¹ = 1520989 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 56333 = 1520991 / (1 + 5 + 2 + 0 + 9 + 9 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1520971) 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, 28140 + ... + 28193.

It is an arithmetic number, because the mean of its divisors is an integer number (281670).

2^1520991 is an apocalyptic number.

1520991 is a deficient number, since it is larger than the sum of its proper divisors (732369).

1520991 is an equidigital number, since it uses as much as digits as its factorization.

1520991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56342 (or 56336 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 1520991 is about 1233.2846386784. The cubic root of 1520991 is about 115.0029236812.

It can be divided in two parts, 152099 and 1, that added together give a square (152100 = 390²).

The spelling of 1520991 in words is "one million, five hundred twenty thousand, nine hundred ninety-one".