21507526504642 has 4 divisors (see below), whose sum is σ = 32261289756966. Its totient is φ = 10753763252320.

The previous prime is 21507526504627. The next prime is 21507526504661. The reversal of 21507526504642 is 24640562570512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 16746092655601 + 4761433849041 = 4092199^2 + 2182071^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5376881626159 + ... + 5376881626162.

Almost surely, 2^{21507526504642} is an apocalyptic number.

21507526504642 is a deficient number, since it is larger than the sum of its proper divisors (10753763252324).

21507526504642 is a wasteful number, since it uses less digits than its factorization.

21507526504642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10753763252323.

The product of its (nonzero) digits is 4032000, while the sum is 49.

The spelling of 21507526504642 in words is "twenty-one trillion, five hundred seven billion, five hundred twenty-six million, five hundred four thousand, six hundred forty-two".