21040052021 has 8 divisors (see below), whose sum is σ = 22149158400. Its totient is φ = 19931119200.

The previous prime is 21040051997. The next prime is 21040052039. The reversal of 21040052021 is 12025004012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21040052021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21040052071) 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 7 ways as a sum of consecutive naturals, for example, 259865 + ... + 331073.

It is an arithmetic number, because the mean of its divisors is an integer number (2768644800).

Almost surely, 2^21040052021 is an apocalyptic number.

It is an amenable number.

21040052021 is a deficient number, since it is larger than the sum of its proper divisors (1109106379).

21040052021 is a wasteful number, since it uses less digits than its factorization.

21040052021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86779.

The product of its (nonzero) digits is 160, while the sum is 17.

Adding to 21040052021 its reverse (12025004012), we get a palindrome (33065056033).

The spelling of 21040052021 in words is "twenty-one billion, forty million, fifty-two thousand, twenty-one".