21388345533 has 12 divisors (see below), whose sum is σ = 30924255648. Its totient is φ = 14245060680.

The previous prime is 21388345501. The next prime is 21388345547. The reversal of 21388345533 is 33554388312.

21388345533 is a `hidden beast` number, since 2 + 1 + 3 + 88 + 34 + 5 + 533 = 666.

It is not a de Polignac number, because 21388345533 - 2⁵ = 21388345501 is a prime.

It is a super-2 number, since 2×21388345533² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21388325533) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1143235 + ... + 1161792.

It is an arithmetic number, because the mean of its divisors is an integer number (2577021304).

Almost surely, 2^21388345533 is an apocalyptic number.

It is an amenable number.

21388345533 is a deficient number, since it is larger than the sum of its proper divisors (9535910115).

21388345533 is a wasteful number, since it uses less digits than its factorization.

21388345533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2306064 (or 2306061 counting only the distinct ones).

The product of its digits is 1036800, while the sum is 45.

The spelling of 21388345533 in words is "twenty-one billion, three hundred eighty-eight million, three hundred forty-five thousand, five hundred thirty-three".