250805561 has 4 divisors (see below), whose sum is σ = 250860624. Its totient is φ = 250750500.

The previous prime is 250805557. The next prime is 250805579. The reversal of 250805561 is 165508052.

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.

It is a cyclic number.

It is not a de Polignac number, because 250805561 - 2² = 250805557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (250805521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20015 + ... + 30036.

It is an arithmetic number, because the mean of its divisors is an integer number (62715156).

Almost surely, 2^250805561 is an apocalyptic number.

It is an amenable number.

250805561 is a deficient number, since it is larger than the sum of its proper divisors (55063).

250805561 is an equidigital number, since it uses as much as digits as its factorization.

250805561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55062.

The product of its (nonzero) digits is 12000, while the sum is 32.

The square root of 250805561 is about 15836.8418884574. The cubic root of 250805561 is about 630.6364283318.

The spelling of 250805561 in words is "two hundred fifty million, eight hundred five thousand, five hundred sixty-one".