21287689530 has 32 divisors (see below), whose sum is σ = 51095836800. Its totient is φ = 5676119232.

The previous prime is 21287689519. The next prime is 21287689531. The reversal of 21287689530 is 3598678212.

It is not an unprimeable number, because it can be changed into a prime (21287689531) 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 15 ways as a sum of consecutive naturals, for example, 302976 + ... + 366564.

It is an arithmetic number, because the mean of its divisors is an integer number (1596744900).

Almost surely, 2^21287689530 is an apocalyptic number.

21287689530 is an abundant number, since it is smaller than the sum of its proper divisors (29808147270).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21287689530 is a wasteful number, since it uses less digits than its factorization.

21287689530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74758.

The product of its (nonzero) digits is 1451520, while the sum is 51.

The spelling of 21287689530 in words is "twenty-one billion, two hundred eighty-seven million, six hundred eighty-nine thousand, five hundred thirty".