21432729650 has 12 divisors (see below), whose sum is σ = 39864877242. Its totient is φ = 8573091840.

The previous prime is 21432729649. The next prime is 21432729667. The reversal of 21432729650 is 5692723412.

It can be written as a sum of positive squares in 3 ways, for example, as 19898205721 + 1534523929 = 141061^2 + 39173^2 .

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21432729598 and 21432729607.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 214327247 + ... + 214327346.

Almost surely, 2^21432729650 is an apocalyptic number.

21432729650 is a deficient number, since it is larger than the sum of its proper divisors (18432147592).

21432729650 is a wasteful number, since it uses less digits than its factorization.

21432729650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428654605 (or 428654600 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 41.

The spelling of 21432729650 in words is "twenty-one billion, four hundred thirty-two million, seven hundred twenty-nine thousand, six hundred fifty".