21720821030 has 32 divisors (see below), whose sum is σ = 39519131904. Its totient is φ = 8594712576.

The previous prime is 21720821027. The next prime is 21720821123. The reversal of 21720821030 is 3012802712.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 2860619 + ... + 2868201.

It is an arithmetic number, because the mean of its divisors is an integer number (1234972872).

Almost surely, 2^21720821030 is an apocalyptic number.

21720821030 is a deficient number, since it is larger than the sum of its proper divisors (17798310874).

21720821030 is a wasteful number, since it uses less digits than its factorization.

21720821030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10640.

The product of its (nonzero) digits is 1344, while the sum is 26.

The spelling of 21720821030 in words is "twenty-one billion, seven hundred twenty million, eight hundred twenty-one thousand, thirty".