21236072655 has 32 divisors (see below), whose sum is σ = 38840108544. Its totient is φ = 9705810816.

The previous prime is 21236072653. The next prime is 21236072657. The reversal of 21236072655 is 55627063212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21236072653) and next prime (21236072657).

It is not a de Polignac number, because 21236072655 - 2¹ = 21236072653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21236072653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 529489 + ... + 568181.

It is an arithmetic number, because the mean of its divisors is an integer number (1213753392).

Almost surely, 2^21236072655 is an apocalyptic number.

21236072655 is a deficient number, since it is larger than the sum of its proper divisors (17604035889).

21236072655 is a wasteful number, since it uses less digits than its factorization.

21236072655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43935.

The product of its (nonzero) digits is 151200, while the sum is 39.

The spelling of 21236072655 in words is "twenty-one billion, two hundred thirty-six million, seventy-two thousand, six hundred fifty-five".