21000250355 has 16 divisors (see below), whose sum is σ = 28802801664. Its totient is φ = 14398942560.

The previous prime is 21000250223. The next prime is 21000250357. The reversal of 21000250355 is 55305200012.

It is not a de Polignac number, because 21000250355 - 2¹⁰ = 21000249331 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21000250355.

It is not an unprimeable number, because it can be changed into a prime (21000250357) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 618470 + ... + 651540.

It is an arithmetic number, because the mean of its divisors is an integer number (1800175104).

Almost surely, 2^21000250355 is an apocalyptic number.

21000250355 is a deficient number, since it is larger than the sum of its proper divisors (7802551309).

21000250355 is a wasteful number, since it uses less digits than its factorization.

21000250355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51226.

The product of its (nonzero) digits is 1500, while the sum is 23.

Adding to 21000250355 its reverse (55305200012), we get a palindrome (76305450367).

The spelling of 21000250355 in words is "twenty-one billion, two hundred fifty thousand, three hundred fifty-five".