21152153332665 has 320 divisors, whose sum is σ = 41260032000000. Its totient is φ = 10333488079872.

The previous prime is 21152153332657. The next prime is 21152153332693. The reversal of 21152153332665 is 56623335125112.

21152153332665 is a `hidden beast` number, since 2 + 1 + 1 + 5 + 21 + 533 + 32 + 6 + 65 = 666.

It is not a de Polignac number, because 21152153332665 - 2³ = 21152153332657 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21152153332665.

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 16538039496 + ... + 16538040774.

It is an arithmetic number, because the mean of its divisors is an integer number (128937600000).

Almost surely, 2^{21152153332665} is an apocalyptic number.

It is an amenable number.

21152153332665 is a deficient number, since it is larger than the sum of its proper divisors (20107878667335).

21152153332665 is a wasteful number, since it uses less digits than its factorization.

21152153332665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1946 (or 1937 counting only the distinct ones).

The product of its digits is 972000, while the sum is 45.

Adding to 21152153332665 its reverse (56623335125112), we get a palindrome (77775488457777).

The spelling of 21152153332665 in words is "twenty-one trillion, one hundred fifty-two billion, one hundred fifty-three million, three hundred thirty-two thousand, six hundred sixty-five".