21161003747 has 4 divisors (see below), whose sum is σ = 22788773280. Its totient is φ = 19533234216.

The previous prime is 21161003719. The next prime is 21161003839. The reversal of 21161003747 is 74730016112.

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

It is a cyclic number.

It is not a de Polignac number, because 21161003747 - 2⁶ = 21161003683 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21161003047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 813884747 + ... + 813884772.

It is an arithmetic number, because the mean of its divisors is an integer number (5697193320).

Almost surely, 2^21161003747 is an apocalyptic number.

21161003747 is a deficient number, since it is larger than the sum of its proper divisors (1627769533).

21161003747 is a wasteful number, since it uses less digits than its factorization.

21161003747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1627769532.

The product of its (nonzero) digits is 7056, while the sum is 32.

Adding to 21161003747 its reverse (74730016112), we get a palindrome (95891019859).

The spelling of 21161003747 in words is "twenty-one billion, one hundred sixty-one million, three thousand, seven hundred forty-seven".