21155523153 has 24 divisors (see below), whose sum is σ = 29866992480. Its totient is φ = 13283078400.

The previous prime is 21155523127. The next prime is 21155523209. The reversal of 21155523153 is 35132555112.

It is a happy number.

It is not a de Polignac number, because 21155523153 - 2¹² = 21155519057 is a prime.

It is a super-2 number, since 2×21155523153² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21155523353) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1699753 + ... + 1712153.

It is an arithmetic number, because the mean of its divisors is an integer number (1244458020).

Almost surely, 2^21155523153 is an apocalyptic number.

It is an amenable number.

21155523153 is a deficient number, since it is larger than the sum of its proper divisors (8711469327).

21155523153 is a wasteful number, since it uses less digits than its factorization.

21155523153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12769 (or 12596 counting only the distinct ones).

The product of its digits is 22500, while the sum is 33.

The spelling of 21155523153 in words is "twenty-one billion, one hundred fifty-five million, five hundred twenty-three thousand, one hundred fifty-three".