618942721 has 4 divisors (see below), whose sum is σ = 618993072. Its totient is φ = 618892372.

The previous prime is 618942637. The next prime is 618942739. The reversal of 618942721 is 127249816.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 618942721 - 2⁷ = 618942593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (618942421) 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, 6810 + ... + 35836.

It is an arithmetic number, because the mean of its divisors is an integer number (154748268).

Almost surely, 2^618942721 is an apocalyptic number.

It is an amenable number.

618942721 is a deficient number, since it is larger than the sum of its proper divisors (50351).

618942721 is a wasteful number, since it uses less digits than its factorization.

618942721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50350.

The product of its digits is 48384, while the sum is 40.

The square root of 618942721 is about 24878.5594639240. The cubic root of 618942721 is about 852.2169215752.

The spelling of 618942721 in words is "six hundred eighteen million, nine hundred forty-two thousand, seven hundred twenty-one".