157549681 has 2 divisors, whose sum is σ = 157549682. Its totient is φ = 157549680.

The previous prime is 157549661. The next prime is 157549697. The reversal of 157549681 is 186945751.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81162081 + 76387600 = 9009^2 + 8740^2 .

It is an emirp because it is prime and its reverse (186945751) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-157549681 is a prime.

It is a super-2 number, since 2×157549681² = 49643803966403522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (157549661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78774840 + 78774841.

It is an arithmetic number, because the mean of its divisors is an integer number (78774841).

Almost surely, 2^157549681 is an apocalyptic number.

It is an amenable number.

157549681 is a deficient number, since it is larger than the sum of its proper divisors (1).

157549681 is an equidigital number, since it uses as much as digits as its factorization.

157549681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 302400, while the sum is 46.

The square root of 157549681 is about 12551.8795803656. The cubic root of 157549681 is about 540.0979257706.

The spelling of 157549681 in words is "one hundred fifty-seven million, five hundred forty-nine thousand, six hundred eighty-one".