42821181 has 24 divisors (see below), whose sum is σ = 70532280. Its totient is φ = 24800256.

The previous prime is 42821171. The next prime is 42821189. The reversal of 42821181 is 18112824.

It can be written as a sum of positive squares in 4 ways, for example, as 1102500 + 41718681 = 1050^2 + 6459^2 .

It is not a de Polignac number, because 42821181 - 2¹³ = 42812989 is a prime.

It is a super-2 number, since 2×42821181² = 3667307084469522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42821189) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8776 + ... + 12753.

It is an arithmetic number, because the mean of its divisors is an integer number (2938845).

Almost surely, 2^42821181 is an apocalyptic number.

It is an amenable number.

42821181 is a deficient number, since it is larger than the sum of its proper divisors (27711099).

42821181 is a wasteful number, since it uses less digits than its factorization.

42821181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21565 (or 21562 counting only the distinct ones).

The product of its digits is 1024, while the sum is 27.

The square root of 42821181 is about 6543.7894984481. The cubic root of 42821181 is about 349.8534924230.

It can be divided in two parts, 428 and 21181, that added together give a square (21609 = 147²).

The spelling of 42821181 in words is "forty-two million, eight hundred twenty-one thousand, one hundred eighty-one".