209746157 has 4 divisors (see below), whose sum is σ = 209855616. Its totient is φ = 209636700.

The previous prime is 209746151. The next prime is 209746169. The reversal of 209746157 is 751647902.

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: 751647902 = 2 ⋅375823951.

It is a cyclic number.

It is not a de Polignac number, because 209746157 - 2¹² = 209742061 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 (209746151) 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 3 ways as a sum of consecutive naturals, for example, 51803 + ... + 55704.

It is an arithmetic number, because the mean of its divisors is an integer number (52463904).

Almost surely, 2^209746157 is an apocalyptic number.

It is an amenable number.

209746157 is a deficient number, since it is larger than the sum of its proper divisors (109459).

209746157 is a wasteful number, since it uses less digits than its factorization.

209746157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109458.

The product of its (nonzero) digits is 105840, while the sum is 41.

The square root of 209746157 is about 14482.6156822585. The cubic root of 209746157 is about 594.1526030014.

The spelling of 209746157 in words is "two hundred nine million, seven hundred forty-six thousand, one hundred fifty-seven".