157649909 has 4 divisors (see below), whose sum is σ = 158304300. Its totient is φ = 156995520.

The previous prime is 157649903. The next prime is 157649923. The reversal of 157649909 is 909946751.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 44823025 + 112826884 = 6695^2 + 10622^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-157649909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (157649903) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 326834 + ... + 327315.

It is an arithmetic number, because the mean of its divisors is an integer number (39576075).

Almost surely, 2^157649909 is an apocalyptic number.

It is an amenable number.

157649909 is a deficient number, since it is larger than the sum of its proper divisors (654391).

157649909 is an equidigital number, since it uses as much as digits as its factorization.

157649909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 654390.

The product of its (nonzero) digits is 612360, while the sum is 50.

The square root of 157649909 is about 12555.8714950417. The cubic root of 157649909 is about 540.2124324232.

The spelling of 157649909 in words is "one hundred fifty-seven million, six hundred forty-nine thousand, nine hundred nine".