21033123550 has 24 divisors (see below), whose sum is σ = 39307039992. Its totient is φ = 8373372000.

The previous prime is 21033123499. The next prime is 21033123593. The reversal of 21033123550 is 5532133012.

It is a super-6 number, since 6×21033123550⁶ (a number of 63 digits) contains 666666 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 986281 + ... + 1007380.

It is an arithmetic number, because the mean of its divisors is an integer number (1637793333).

Almost surely, 2^21033123550 is an apocalyptic number.

21033123550 is a deficient number, since it is larger than the sum of its proper divisors (18273916442).

21033123550 is a wasteful number, since it uses less digits than its factorization.

21033123550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1993884 (or 1993879 counting only the distinct ones).

The product of its (nonzero) digits is 2700, while the sum is 25.

Adding to 21033123550 its reverse (5532133012), we get a palindrome (26565256562).

The spelling of 21033123550 in words is "twenty-one billion, thirty-three million, one hundred twenty-three thousand, five hundred fifty".