42861981 has 16 divisors (see below), whose sum is σ = 60787584. Its totient is φ = 26770944.

The previous prime is 42861941. The next prime is 42861983. The reversal of 42861981 is 18916824.

It is not a de Polignac number, because 42861981 - 2¹⁰ = 42860957 is a prime.

It is a super-2 number, since 2×42861981² = 3674298830488722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42861983) 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, 10080 + ... + 13686.

It is an arithmetic number, because the mean of its divisors is an integer number (3799224).

Almost surely, 2^42861981 is an apocalyptic number.

It is an amenable number.

42861981 is a deficient number, since it is larger than the sum of its proper divisors (17925603).

42861981 is a wasteful number, since it uses less digits than its factorization.

42861981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3860.

The product of its digits is 27648, while the sum is 39.

The square root of 42861981 is about 6546.9062159160. The cubic root of 42861981 is about 349.9645705634.

The spelling of 42861981 in words is "forty-two million, eight hundred sixty-one thousand, nine hundred eighty-one".