139997551 has 8 divisors (see below), whose sum is σ = 143693264. Its totient is φ = 136321920.

The previous prime is 139997531. The next prime is 139997591. The reversal of 139997551 is 155799931.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 7-Lehmer number, since φ(139997551) divides (139997551-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 139997551 - 2¹⁷ = 139866479 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 139997495 and 139997504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139997531) 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 7 ways as a sum of consecutive naturals, for example, 9661 + ... + 19321.

It is an arithmetic number, because the mean of its divisors is an integer number (17961658).

Almost surely, 2^139997551 is an apocalyptic number.

139997551 is the 9661-st pentagonal number.

139997551 is the 6325-th centered heptagonal number.

139997551 is a deficient number, since it is larger than the sum of its proper divisors (3695713).

139997551 is an equidigital number, since it uses as much as digits as its factorization.

139997551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10041.

The product of its digits is 382725, while the sum is 49.

The square root of 139997551 is about 11832.0560766082. The cubic root of 139997551 is about 519.2463824489.

The spelling of 139997551 in words is "one hundred thirty-nine million, nine hundred ninety-seven thousand, five hundred fifty-one".