240778721 has 4 divisors (see below), whose sum is σ = 247286292. Its totient is φ = 234271152.

The previous prime is 240778717. The next prime is 240778729. The reversal of 240778721 is 127877042.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127877042 = 2 ⋅63938521.

It can be written as a sum of positive squares in 2 ways, for example, as 152794321 + 87984400 = 12361^2 + 9380^2 .

It is a cyclic number.

It is not a de Polignac number, because 240778721 - 2² = 240778717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (240778729) 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, 3253730 + ... + 3253803.

It is an arithmetic number, because the mean of its divisors is an integer number (61821573).

Almost surely, 2^240778721 is an apocalyptic number.

It is an amenable number.

240778721 is a deficient number, since it is larger than the sum of its proper divisors (6507571).

240778721 is an equidigital number, since it uses as much as digits as its factorization.

240778721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6507570.

The product of its (nonzero) digits is 43904, while the sum is 38.

The square root of 240778721 is about 15517.0461428714. The cubic root of 240778721 is about 622.1179053307.

The spelling of 240778721 in words is "two hundred forty million, seven hundred seventy-eight thousand, seven hundred twenty-one".