138148821 has 20 divisors (see below), whose sum is σ = 207463212. Its totient is φ = 91611648.

The previous prime is 138148807. The next prime is 138148823. The reversal of 138148821 is 128841831.

It can be written as a sum of positive squares in 2 ways, for example, as 101787921 + 36360900 = 10089^2 + 6030^2 .

It is not a de Polignac number, because 138148821 - 2¹⁴ = 138132437 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138148823) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 11215 + ... + 20051.

Almost surely, 2^138148821 is an apocalyptic number.

It is an amenable number.

138148821 is a deficient number, since it is larger than the sum of its proper divisors (69314391).

138148821 is an equidigital number, since it uses as much as digits as its factorization.

138148821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9042 (or 9033 counting only the distinct ones).

The product of its digits is 12288, while the sum is 36.

The square root of 138148821 is about 11753.6726600667. The cubic root of 138148821 is about 516.9506205122.

The spelling of 138148821 in words is "one hundred thirty-eight million, one hundred forty-eight thousand, eight hundred twenty-one".