139781421 has 36 divisors (see below), whose sum is σ = 226242900. Its totient is φ = 83026944.

The previous prime is 139781417. The next prime is 139781437. The reversal of 139781421 is 124187931.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 5546025 + 134235396 = 2355^2 + 11586^2 .

It is not a de Polignac number, because 139781421 - 2² = 139781417 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139781401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 42525 + ... + 45693.

It is an arithmetic number, because the mean of its divisors is an integer number (6284525).

Almost surely, 2^139781421 is an apocalyptic number.

It is an amenable number.

139781421 is a deficient number, since it is larger than the sum of its proper divisors (86461479).

139781421 is a wasteful number, since it uses less digits than its factorization.

139781421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3230 (or 3214 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 139781421 is about 11822.9193095445. The cubic root of 139781421 is about 518.9790384353.

The spelling of 139781421 in words is "one hundred thirty-nine million, seven hundred eighty-one thousand, four hundred twenty-one".