21347721530 has 16 divisors (see below), whose sum is σ = 38455871904. Its totient is φ = 8532427920.

The previous prime is 21347721511. The next prime is 21347721533. The reversal of 21347721530 is 3512774312.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21347721533) 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 7 ways as a sum of consecutive naturals, for example, 819116 + ... + 844775.

It is an arithmetic number, because the mean of its divisors is an integer number (2403491994).

Almost surely, 2^21347721530 is an apocalyptic number.

21347721530 is a deficient number, since it is larger than the sum of its proper divisors (17108150374).

21347721530 is a wasteful number, since it uses less digits than its factorization.

21347721530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1665181.

The product of its (nonzero) digits is 35280, while the sum is 35.

The spelling of 21347721530 in words is "twenty-one billion, three hundred forty-seven million, seven hundred twenty-one thousand, five hundred thirty".