21030345621 has 12 divisors (see below), whose sum is σ = 30805014240. Its totient is φ = 13822761960.

The previous prime is 21030345617. The next prime is 21030345629. The reversal of 21030345621 is 12654303012.

21030345621 is a `hidden beast` number, since 2 + 1 + 0 + 3 + 0 + 34 + 5 + 621 = 666.

It is not a de Polignac number, because 21030345621 - 2² = 21030345617 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21030345629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16455031 + ... + 16456308.

It is an arithmetic number, because the mean of its divisors is an integer number (2567084520).

Almost surely, 2^21030345621 is an apocalyptic number.

It is an amenable number.

21030345621 is a deficient number, since it is larger than the sum of its proper divisors (9774668619).

21030345621 is a wasteful number, since it uses less digits than its factorization.

21030345621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32911416 (or 32911413 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

Adding to 21030345621 its reverse (12654303012), we get a palindrome (33684648633).

The spelling of 21030345621 in words is "twenty-one billion, thirty million, three hundred forty-five thousand, six hundred twenty-one".