21655050651 has 32 divisors (see below), whose sum is σ = 35663882240. Its totient is φ = 12896301600.

The previous prime is 21655050649. The next prime is 21655050661. The reversal of 21655050651 is 15605055612.

21655050651 is a `hidden beast` number, since 2 + 1 + 6 + 550 + 50 + 6 + 51 = 666.

It is not a de Polignac number, because 21655050651 - 2¹ = 21655050649 is a prime.

It is a super-3 number, since 3×21655050651³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21655050661) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 984205 + ... + 1005966.

It is an arithmetic number, because the mean of its divisors is an integer number (1114496320).

Almost surely, 2^21655050651 is an apocalyptic number.

21655050651 is a deficient number, since it is larger than the sum of its proper divisors (14008831589).

21655050651 is a wasteful number, since it uses less digits than its factorization.

21655050651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1990224 (or 1990218 counting only the distinct ones).

The product of its (nonzero) digits is 45000, while the sum is 36.

The spelling of 21655050651 in words is "twenty-one billion, six hundred fifty-five million, fifty thousand, six hundred fifty-one".