42115821 has 8 divisors (see below), whose sum is σ = 61259424. Its totient is φ = 25524720.

The previous prime is 42115813. The next prime is 42115831. The reversal of 42115821 is 12851124.

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

It is not a de Polignac number, because 42115821 - 2³ = 42115813 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 42115791 and 42115800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42115831) 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, 638086 + ... + 638151.

It is an arithmetic number, because the mean of its divisors is an integer number (7657428).

Almost surely, 2^42115821 is an apocalyptic number.

It is an amenable number.

42115821 is a deficient number, since it is larger than the sum of its proper divisors (19143603).

42115821 is a wasteful number, since it uses less digits than its factorization.

42115821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1276251.

The product of its digits is 640, while the sum is 24.

The square root of 42115821 is about 6489.6703306100. The cubic root of 42115821 is about 347.9218925642.

Adding to 42115821 its reverse (12851124), we get a palindrome (54966945).

The spelling of 42115821 in words is "forty-two million, one hundred fifteen thousand, eight hundred twenty-one".