256143649 has 4 divisors (see below), whose sum is σ = 256241664. Its totient is φ = 256045636.

The previous prime is 256143619. The next prime is 256143659. The reversal of 256143649 is 946341652.

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 256143649 - 2⁷ = 256143521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256143619) 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, 44977 + ... + 50350.

It is an arithmetic number, because the mean of its divisors is an integer number (64060416).

Almost surely, 2^256143649 is an apocalyptic number.

It is an amenable number.

256143649 is a deficient number, since it is larger than the sum of its proper divisors (98015).

256143649 is an equidigital number, since it uses as much as digits as its factorization.

256143649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98014.

The product of its digits is 155520, while the sum is 40.

The square root of 256143649 is about 16004.4884016953. The cubic root of 256143649 is about 635.0791634622.

The spelling of 256143649 in words is "two hundred fifty-six million, one hundred forty-three thousand, six hundred forty-nine".