138021536 has 12 divisors (see below), whose sum is σ = 271729962. Its totient is φ = 69010752.

The previous prime is 138021509. The next prime is 138021553. The reversal of 138021536 is 635120831.

It can be written as a sum of positive squares in only one way, i.e., 109077136 + 28944400 = 10444^2 + 5380^2 .

It is a junction number, because it is equal to n+sod(n) for n = 138021499 and 138021508.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2156555 + ... + 2156618.

Almost surely, 2^138021536 is an apocalyptic number.

138021536 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

138021536 is a deficient number, since it is larger than the sum of its proper divisors (133708426).

138021536 is an equidigital number, since it uses as much as digits as its factorization.

138021536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4313183 (or 4313175 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 138021536 is about 11748.2567217439. The cubic root of 138021536 is about 516.7918056000.

The spelling of 138021536 in words is "one hundred thirty-eight million, twenty-one thousand, five hundred thirty-six".