21000255507 has 96 divisors (see below), whose sum is σ = 40755456000. Its totient is φ = 10557086400.

The previous prime is 21000255439. The next prime is 21000255517. The reversal of 21000255507 is 70555200012.

It is a happy number.

21000255507 is a `hidden beast` number, since 2 + 100 + 0 + 2 + 5 + 550 + 7 = 666.

It is not a de Polignac number, because 21000255507 - 2¹² = 21000251411 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21000255517) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 427869 + ... + 474417.

It is an arithmetic number, because the mean of its divisors is an integer number (424536000).

Almost surely, 2^21000255507 is an apocalyptic number.

21000255507 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21000255507 is a deficient number, since it is larger than the sum of its proper divisors (19755200493).

21000255507 is a wasteful number, since it uses less digits than its factorization.

21000255507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46614 (or 46601 counting only the distinct ones).

The product of its (nonzero) digits is 3500, while the sum is 27.

Adding to 21000255507 its reverse (70555200012), we get a palindrome (91555455519).

The spelling of 21000255507 in words is "twenty-one billion, two hundred fifty-five thousand, five hundred seven".