243791961 has 32 divisors (see below), whose sum is σ = 382341120. Its totient is φ = 135288576.

The previous prime is 243791957. The next prime is 243791971. The reversal of 243791961 is 169197342.

It is not a de Polignac number, because 243791961 - 2² = 243791957 is a prime.

It is not an unprimeable number, because it can be changed into a prime (243791971) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 136305 + ... + 138081.

It is an arithmetic number, because the mean of its divisors is an integer number (11948160).

Almost surely, 2^243791961 is an apocalyptic number.

243791961 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

243791961 is a deficient number, since it is larger than the sum of its proper divisors (138549159).

243791961 is a wasteful number, since it uses less digits than its factorization.

243791961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1973.

The product of its digits is 81648, while the sum is 42.

The square root of 243791961 is about 15613.8387656591. The cubic root of 243791961 is about 624.7023316388.

The spelling of 243791961 in words is "two hundred forty-three million, seven hundred ninety-one thousand, nine hundred sixty-one".