138001621 has 2 divisors, whose sum is σ = 138001622. Its totient is φ = 138001620.

The previous prime is 138001519. The next prime is 138001637. The reversal of 138001621 is 126100831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 136632721 + 1368900 = 11689^2 + 1170^2 .

It is a cyclic number.

It is not a de Polignac number, because 138001621 - 2⁹ = 138001109 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 138001592 and 138001601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138001651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69000810 + 69000811.

It is an arithmetic number, because the mean of its divisors is an integer number (69000811).

Almost surely, 2^138001621 is an apocalyptic number.

It is an amenable number.

138001621 is a deficient number, since it is larger than the sum of its proper divisors (1).

138001621 is an equidigital number, since it uses as much as digits as its factorization.

138001621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 138001621 is about 11747.4091186099. The cubic root of 138001621 is about 516.7669486003.

The spelling of 138001621 in words is "one hundred thirty-eight million, one thousand, six hundred twenty-one".