21928920651 has 24 divisors (see below), whose sum is σ = 34562211840. Its totient is φ = 13287351600.

The previous prime is 21928920649. The next prime is 21928920677. The reversal of 21928920651 is 15602982912.

It is a happy number.

It is not a de Polignac number, because 21928920651 - 2¹ = 21928920649 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21928920597 and 21928920606.

It is not an unprimeable number, because it can be changed into a prime (21928220651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 485146 + ... + 528416.

It is an arithmetic number, because the mean of its divisors is an integer number (1440092160).

Almost surely, 2^21928920651 is an apocalyptic number.

21928920651 is a deficient number, since it is larger than the sum of its proper divisors (12633291189).

21928920651 is a wasteful number, since it uses less digits than its factorization.

21928920651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48407 (or 48404 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The spelling of 21928920651 in words is "twenty-one billion, nine hundred twenty-eight million, nine hundred twenty thousand, six hundred fifty-one".