21438133028 has 24 divisors (see below), whose sum is σ = 41164954488. Its totient is φ = 9707832576.

The previous prime is 21438133027. The next prime is 21438133039. The reversal of 21438133028 is 82033183412.

It can be written as a sum of positive squares in 4 ways, for example, as 5692400704 + 15745732324 = 75448^2 + 125482^2 .

It is not an unprimeable number, because it can be changed into a prime (21438133027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3886601 + ... + 3892112.

It is an arithmetic number, because the mean of its divisors is an integer number (1715206437).

Almost surely, 2^21438133028 is an apocalyptic number.

It is an amenable number.

21438133028 is a deficient number, since it is larger than the sum of its proper divisors (19726821460).

21438133028 is a wasteful number, since it uses less digits than its factorization.

21438133028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7778783 (or 7778781 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 35.

The spelling of 21438133028 in words is "twenty-one billion, four hundred thirty-eight million, one hundred thirty-three thousand, twenty-eight".