138407428 has 6 divisors (see below), whose sum is σ = 242213006. Its totient is φ = 69203712.

The previous prime is 138407407. The next prime is 138407453. The reversal of 138407428 is 824704831.

138407428 is digitally balanced in base 2 and base 3, because in such bases 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., 103266244 + 35141184 = 10162^2 + 5928^2 .

It is a super-2 number, since 2×138407428² = 38313232251150368, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 17300925 + ... + 17300932.

Almost surely, 2^138407428 is an apocalyptic number.

It is an amenable number.

138407428 is a deficient number, since it is larger than the sum of its proper divisors (103805578).

138407428 is a wasteful number, since it uses less digits than its factorization.

138407428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34601861 (or 34601859 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 37.

The square root of 138407428 is about 11764.6686311175. The cubic root of 138407428 is about 517.2729871613.

The spelling of 138407428 in words is "one hundred thirty-eight million, four hundred seven thousand, four hundred twenty-eight".