21533555505 has 64 divisors (see below), whose sum is σ = 42983405568. Its totient is φ = 8943144960.

The previous prime is 21533555501. The next prime is 21533555509. The reversal of 21533555505 is 50555533512.

It is an interprime number because it is at equal distance from previous prime (21533555501) and next prime (21533555509).

It is not a de Polignac number, because 21533555505 - 2² = 21533555501 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21533555501) 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, 2058769 + ... + 2069201.

It is an arithmetic number, because the mean of its divisors is an integer number (671615712).

Almost surely, 2^21533555505 is an apocalyptic number.

It is an amenable number.

21533555505 is a deficient number, since it is larger than the sum of its proper divisors (21449850063).

21533555505 is a wasteful number, since it uses less digits than its factorization.

21533555505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12246.

The product of its (nonzero) digits is 281250, while the sum is 39.

The spelling of 21533555505 in words is "twenty-one billion, five hundred thirty-three million, five hundred fifty-five thousand, five hundred five".