42131621 has 12 divisors (see below), whose sum is σ = 49566060. Its totient is φ = 35703360.

The previous prime is 42131603. The next prime is 42131623. The reversal of 42131621 is 12613124.

It can be written as a sum of positive squares in 2 ways, for example, as 2265025 + 39866596 = 1505^2 + 6314^2 .

It is not a de Polignac number, because 42131621 - 2¹⁰ = 42130597 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42131593 and 42131602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42131623) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 470 + ... + 9191.

It is an arithmetic number, because the mean of its divisors is an integer number (4130505).

Almost surely, 2^42131621 is an apocalyptic number.

It is an amenable number.

42131621 is a deficient number, since it is larger than the sum of its proper divisors (7434439).

42131621 is an equidigital number, since it uses as much as digits as its factorization.

42131621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9764 (or 9757 counting only the distinct ones).

The product of its digits is 288, while the sum is 20.

The square root of 42131621 is about 6490.8875356148. The cubic root of 42131621 is about 347.9653954449.

Adding to 42131621 its reverse (12613124), we get a palindrome (54744745).

The spelling of 42131621 in words is "forty-two million, one hundred thirty-one thousand, six hundred twenty-one".