1819563981 has 8 divisors (see below), whose sum is σ = 2427453120. Its totient is φ = 1212358752.

The previous prime is 1819563979. The next prime is 1819564007. The reversal of 1819563981 is 1893659181.

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

It is not a de Polignac number, because 1819563981 - 2¹ = 1819563979 is a prime.

It is a super-2 number, since 2×1819563981² = 6621626161905136722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1819563901) 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, 164736 + ... + 175433.

It is an arithmetic number, because the mean of its divisors is an integer number (303431640).

Almost surely, 2^1819563981 is an apocalyptic number.

It is an amenable number.

1819563981 is a deficient number, since it is larger than the sum of its proper divisors (607889139).

1819563981 is a wasteful number, since it uses less digits than its factorization.

1819563981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341955.

The product of its digits is 466560, while the sum is 51.

The square root of 1819563981 is about 42656.3474878007. The cubic root of 1819563981 is about 1220.8316422698.

The spelling of 1819563981 in words is "one billion, eight hundred nineteen million, five hundred sixty-three thousand, nine hundred eighty-one".