139821861 has 4 divisors (see below), whose sum is σ = 186429152. Its totient is φ = 93214572.

The previous prime is 139821859. The next prime is 139821881. The reversal of 139821861 is 168128931.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 139821861 - 2¹ = 139821859 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139821841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23303641 + ... + 23303646.

It is an arithmetic number, because the mean of its divisors is an integer number (46607288).

Almost surely, 2^139821861 is an apocalyptic number.

It is an amenable number.

139821861 is a deficient number, since it is larger than the sum of its proper divisors (46607291).

139821861 is an equidigital number, since it uses as much as digits as its factorization.

139821861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46607290.

The product of its digits is 20736, while the sum is 39.

The square root of 139821861 is about 11824.6294233688. The cubic root of 139821861 is about 519.0290820165.

The spelling of 139821861 in words is "one hundred thirty-nine million, eight hundred twenty-one thousand, eight hundred sixty-one".