21209386653 has 64 divisors (see below), whose sum is σ = 39920025600. Its totient is φ = 10826447040.

The previous prime is 21209386621. The next prime is 21209386697. The reversal of 21209386653 is 35668390212.

21209386653 is a `hidden beast` number, since 2 + 1 + 209 + 386 + 65 + 3 = 666.

It is not a de Polignac number, because 21209386653 - 2⁵ = 21209386621 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21209386599 and 21209386608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21209386613) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 63063 + ... + 215396.

It is an arithmetic number, because the mean of its divisors is an integer number (623750400).

Almost surely, 2^21209386653 is an apocalyptic number.

It is an amenable number.

21209386653 is a deficient number, since it is larger than the sum of its proper divisors (18710638947).

21209386653 is a wasteful number, since it uses less digits than its factorization.

21209386653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278519 (or 278513 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 45.

The spelling of 21209386653 in words is "twenty-one billion, two hundred nine million, three hundred eighty-six thousand, six hundred fifty-three".