139749217 has 2 divisors, whose sum is σ = 139749218. Its totient is φ = 139749216.

The previous prime is 139749187. The next prime is 139749221. The reversal of 139749217 is 712947931.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125641681 + 14107536 = 11209^2 + 3756^2 .

It is a cyclic number.

It is not a de Polignac number, because 139749217 - 2⁷ = 139749089 is a prime.

It is a super-2 number, since 2×139749217² = 39059687304226178, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (139749277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69874608 + 69874609.

It is an arithmetic number, because the mean of its divisors is an integer number (69874609).

Almost surely, 2^139749217 is an apocalyptic number.

It is an amenable number.

139749217 is a deficient number, since it is larger than the sum of its proper divisors (1).

139749217 is an equidigital number, since it uses as much as digits as its factorization.

139749217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 95256, while the sum is 43.

The square root of 139749217 is about 11821.5573001191. The cubic root of 139749217 is about 518.9391798129.

The spelling of 139749217 in words is "one hundred thirty-nine million, seven hundred forty-nine thousand, two hundred seventeen".