42021081 has 6 divisors (see below), whose sum is σ = 60697130. Its totient is φ = 28014048.

The previous prime is 42021073. The next prime is 42021121. The reversal of 42021081 is 18012024.

It can be written as a sum of positive squares in only one way, i.e., 40755456 + 1265625 = 6384^2 + 1125^2 .

It is not a de Polignac number, because 42021081 - 2³ = 42021073 is a prime.

It is a super-2 number, since 2×42021081² = 3531542496817122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (42021071) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2334496 + ... + 2334513.

Almost surely, 2^42021081 is an apocalyptic number.

It is an amenable number.

42021081 is a deficient number, since it is larger than the sum of its proper divisors (18676049).

42021081 is a wasteful number, since it uses less digits than its factorization.

42021081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4669015 (or 4669012 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 42021081 is about 6482.3669288309. The cubic root of 42021081 is about 347.6608119974.

The spelling of 42021081 in words is "forty-two million, twenty-one thousand, eighty-one".