521370139 has 4 divisors (see below), whose sum is σ = 521417800. Its totient is φ = 521322480.

The previous prime is 521370137. The next prime is 521370167. The reversal of 521370139 is 931073125.

521370139 = T₁₈₆₄₂ + T₁₈₆₄₃ + T₁₈₆₄₄.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 521370139 - 2¹ = 521370137 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 521370139.

It is not an unprimeable number, because it can be changed into a prime (521370131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1687 + ... + 32335.

It is an arithmetic number, because the mean of its divisors is an integer number (130354450).

Almost surely, 2^521370139 is an apocalyptic number.

521370139 is the 18644-th centered triangular number.

521370139 is a deficient number, since it is larger than the sum of its proper divisors (47661).

521370139 is a wasteful number, since it uses less digits than its factorization.

521370139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47660.

The product of its (nonzero) digits is 5670, while the sum is 31.

The square root of 521370139 is about 22833.5310234751. The cubic root of 521370139 is about 804.8508083535.

The spelling of 521370139 in words is "five hundred twenty-one million, three hundred seventy thousand, one hundred thirty-nine".