139719978 has 40 divisors (see below), whose sum is σ = 319002948. Its totient is φ = 45691776.

The previous prime is 139719971. The next prime is 139719997. The reversal of 139719978 is 879917931.

139719978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 117223929 + 22496049 = 10827^2 + 4743^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (139719971) 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, 450 + ... + 16722.

Almost surely, 2^139719978 is an apocalyptic number.

139719978 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 139719978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159501474).

139719978 is an abundant number, since it is smaller than the sum of its proper divisors (179282970).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

139719978 is a wasteful number, since it uses less digits than its factorization.

139719978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16340 (or 16331 counting only the distinct ones).

The product of its digits is 857304, while the sum is 54.

The square root of 139719978 is about 11820.3205540290. The cubic root of 139719978 is about 518.9029856423.

The spelling of 139719978 in words is "one hundred thirty-nine million, seven hundred nineteen thousand, nine hundred seventy-eight".