1812461981 has 8 divisors (see below), whose sum is σ = 2045412000. Its totient is φ = 1590875440.

The previous prime is 1812461977. The next prime is 1812461999. The reversal of 1812461981 is 1891642181.

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

It is not a de Polignac number, because 1812461981 - 2² = 1812461977 is a prime.

It is a super-2 number, since 2×1812461981² = 6570036865140888722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1812461941) 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, 2840531 + ... + 2841168.

It is an arithmetic number, because the mean of its divisors is an integer number (255676500).

Almost surely, 2^1812461981 is an apocalyptic number.

1812461981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1812461981 is a deficient number, since it is larger than the sum of its proper divisors (232950019).

1812461981 is a wasteful number, since it uses less digits than its factorization.

1812461981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5681739.

The product of its digits is 27648, while the sum is 41.

The square root of 1812461981 is about 42573.0194019640. The cubic root of 1812461981 is about 1219.2412152145.

The spelling of 1812461981 in words is "one billion, eight hundred twelve million, four hundred sixty-one thousand, nine hundred eighty-one".