1981567 has 16 divisors (see below), whose sum is σ = 2442240. Its totient is φ = 1569888.

The previous prime is 1981547. The next prime is 1981583. The reversal of 1981567 is 7651891.

It is a cyclic number.

It is not a de Polignac number, because 1981567 - 2¹⁵ = 1948799 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981517) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6093 + ... + 6409.

It is an arithmetic number, because the mean of its divisors is an integer number (152640).

2^1981567 is an apocalyptic number.

1981567 is a deficient number, since it is larger than the sum of its proper divisors (460673).

1981567 is a wasteful number, since it uses less digits than its factorization.

1981567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390.

The product of its digits is 15120, while the sum is 37.

The square root of 1981567 is about 1407.6814270281. The cubic root of 1981567 is about 125.6038409782.

The spelling of 1981567 in words is "one million, nine hundred eighty-one thousand, five hundred sixty-seven".