137728405 has 4 divisors (see below), whose sum is σ = 165274092. Its totient is φ = 110182720.

The previous prime is 137728399. The next prime is 137728411. The reversal of 137728405 is 504827731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 504827731 = 461 ⋅1095071.

It is an interprime number because it is at equal distance from previous prime (137728399) and next prime (137728411).

It can be written as a sum of positive squares in 2 ways, for example, as 34644996 + 103083409 = 5886^2 + 10153^2 .

It is not a de Polignac number, because 137728405 - 2⁷ = 137728277 is a prime.

It is a super-2 number, since 2×137728405² = 37938227087688050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13772836 + ... + 13772845.

It is an arithmetic number, because the mean of its divisors is an integer number (41318523).

Almost surely, 2^137728405 is an apocalyptic number.

It is an amenable number.

137728405 is a deficient number, since it is larger than the sum of its proper divisors (27545687).

137728405 is an equidigital number, since it uses as much as digits as its factorization.

137728405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27545686.

The product of its (nonzero) digits is 47040, while the sum is 37.

The square root of 137728405 is about 11735.7745803164. The cubic root of 137728405 is about 516.4256910709.

The spelling of 137728405 in words is "one hundred thirty-seven million, seven hundred twenty-eight thousand, four hundred five".