16521100042 has 4 divisors (see below), whose sum is σ = 24781650066. Its totient is φ = 8260550020.

The previous prime is 16521100033. The next prime is 16521100111. The reversal of 16521100042 is 24000112561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24000112561 = 19 ⋅1263163819.

It can be written as a sum of positive squares in only one way, i.e., 12882477001 + 3638623041 = 113501^2 + 60321^2 .

It is a junction number, because it is equal to n+sod(n) for n = 16521099986 and 16521100022.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4130275009 + ... + 4130275012.

Almost surely, 2^16521100042 is an apocalyptic number.

16521100042 is a deficient number, since it is larger than the sum of its proper divisors (8260550024).

16521100042 is an equidigital number, since it uses as much as digits as its factorization.

16521100042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8260550023.

The product of its (nonzero) digits is 480, while the sum is 22.

The spelling of 16521100042 in words is "sixteen billion, five hundred twenty-one million, one hundred thousand, forty-two".