157993709 has 4 divisors (see below), whose sum is σ = 158037504. Its totient is φ = 157949916.

The previous prime is 157993691. The next prime is 157993723. The reversal of 157993709 is 907399751.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 907399751 = 26839 ⋅33809.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-157993709 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 (157993009) 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, 15947 + ... + 23880.

It is an arithmetic number, because the mean of its divisors is an integer number (39509376).

Almost surely, 2^157993709 is an apocalyptic number.

It is an amenable number.

157993709 is a deficient number, since it is larger than the sum of its proper divisors (43795).

157993709 is an equidigital number, since it uses as much as digits as its factorization.

157993709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43794.

The product of its (nonzero) digits is 535815, while the sum is 50.

The square root of 157993709 is about 12569.5548449418. The cubic root of 157993709 is about 540.6048423950.

The spelling of 157993709 in words is "one hundred fifty-seven million, nine hundred ninety-three thousand, seven hundred nine".