42151221531 has 24 divisors (see below), whose sum is σ = 63189934080. Its totient is φ = 28078636392.

The previous prime is 42151221499. The next prime is 42151221577. The reversal of 42151221531 is 13512215124.

It is a happy number.

42151221531 is a `hidden beast` number, since 4 + 2 + 1 + 5 + 122 + 1 + 531 = 666.

It is not a de Polignac number, because 42151221531 - 2⁵ = 42151221499 is a prime.

It is a super-2 number, since 2×42151221531² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 42151221495 and 42151221504.

It is not an unprimeable number, because it can be changed into a prime (42151226531) 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, 242986 + ... + 378608.

It is an arithmetic number, because the mean of its divisors is an integer number (2632913920).

Almost surely, 2^42151221531 is an apocalyptic number.

42151221531 is a deficient number, since it is larger than the sum of its proper divisors (21038712549).

42151221531 is a wasteful number, since it uses less digits than its factorization.

42151221531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136917 (or 136905 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

Adding to 42151221531 its reverse (13512215124), we get a palindrome (55663436655).

The spelling of 42151221531 in words is "forty-two billion, one hundred fifty-one million, two hundred twenty-one thousand, five hundred thirty-one".