1981569 has 8 divisors (see below), whose sum is σ = 2703712. Its totient is φ = 1290240.

The previous prime is 1981547. The next prime is 1981583. The reversal of 1981569 is 9651891.

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

It is not a de Polignac number, because 1981569 - 2¹⁵ = 1948801 is a prime.

It is a super-2 number, since 2×1981569² = 7853231403522, which contains 22 as substring.

It is a Duffinian number.

1981569 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1981589) 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, 7552 + ... + 7809.

It is an arithmetic number, because the mean of its divisors is an integer number (337964).

2^1981569 is an apocalyptic number.

It is an amenable number.

1981569 is a deficient number, since it is larger than the sum of its proper divisors (722143).

1981569 is a wasteful number, since it uses less digits than its factorization.

1981569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15407.

The product of its digits is 19440, while the sum is 39.

The square root of 1981569 is about 1407.6821374160. The cubic root of 1981569 is about 125.6038832356.

The spelling of 1981569 in words is "one million, nine hundred eighty-one thousand, five hundred sixty-nine".