1563981 has 16 divisors (see below), whose sum is σ = 2193408. Its totient is φ = 990000.

The previous prime is 1563973. The next prime is 1564001. The reversal of 1563981 is 1893651.

It is not a de Polignac number, because 1563981 - 2³ = 1563973 is a prime.

It is a super-2 number, since 2×1563981² = 4892073136722, which contains 22 as substring.

1563981 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1563901) 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, 6106 + ... + 6356.

It is an arithmetic number, because the mean of its divisors is an integer number (137088).

2^1563981 is an apocalyptic number.

It is an amenable number.

1563981 is a deficient number, since it is larger than the sum of its proper divisors (629427).

1563981 is a wasteful number, since it uses less digits than its factorization.

1563981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352.

The product of its digits is 6480, while the sum is 33.

The square root of 1563981 is about 1250.5922596914. The cubic root of 1563981 is about 116.0763716261.

The spelling of 1563981 in words is "one million, five hundred sixty-three thousand, nine hundred eighty-one".