1918724221 has 8 divisors (see below), whose sum is σ = 1928015424. Its totient is φ = 1909447680.

The previous prime is 1918724167. The next prime is 1918724231. The reversal of 1918724221 is 1224278191.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1918724221 - 2¹¹ = 1918722173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1918724231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 328896 + ... + 334678.

It is an arithmetic number, because the mean of its divisors is an integer number (241001928).

Almost surely, 2^1918724221 is an apocalyptic number.

It is an amenable number.

1918724221 is a deficient number, since it is larger than the sum of its proper divisors (9291203).

1918724221 is a wasteful number, since it uses less digits than its factorization.

1918724221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7331.

The product of its digits is 16128, while the sum is 37.

The square root of 1918724221 is about 43803.2444118013. The cubic root of 1918724221 is about 1242.6176537483.

The spelling of 1918724221 in words is "one billion, nine hundred eighteen million, seven hundred twenty-four thousand, two hundred twenty-one".