249540561 has 8 divisors (see below), whose sum is σ = 369689760. Its totient is φ = 166360356.

The previous prime is 249540527. The next prime is 249540587. The reversal of 249540561 is 165045942.

249540561 is a `hidden beast` number, since 2 + 4 + 95 + 4 + 0 + 561 = 666.

It is not a de Polignac number, because 249540561 - 2⁶ = 249540497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (249540521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4621095 + ... + 4621148.

It is an arithmetic number, because the mean of its divisors is an integer number (46211220).

Almost surely, 2^249540561 is an apocalyptic number.

It is an amenable number.

249540561 is a deficient number, since it is larger than the sum of its proper divisors (120149199).

249540561 is an equidigital number, since it uses as much as digits as its factorization.

249540561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9242252 (or 9242246 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 249540561 is about 15796.8528827738. The cubic root of 249540561 is about 629.5743837281.

The spelling of 249540561 in words is "two hundred forty-nine million, five hundred forty thousand, five hundred sixty-one".