138021428 has 6 divisors (see below), whose sum is σ = 241537506. Its totient is φ = 69010712.

The previous prime is 138021361. The next prime is 138021431. The reversal of 138021428 is 824120831.

138021428 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 96393124 + 41628304 = 9818^2 + 6452^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 138021428.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 17252675 + ... + 17252682.

It is an arithmetic number, because the mean of its divisors is an integer number (40256251).

Almost surely, 2^138021428 is an apocalyptic number.

It is an amenable number.

138021428 is a deficient number, since it is larger than the sum of its proper divisors (103516078).

138021428 is a wasteful number, since it uses less digits than its factorization.

138021428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34505361 (or 34505359 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 138021428 is about 11748.2521253163. The cubic root of 138021428 is about 516.7916708058.

The spelling of 138021428 in words is "one hundred thirty-eight million, twenty-one thousand, four hundred twenty-eight".