2181238747 has 4 divisors (see below), whose sum is σ = 2181407976. Its totient is φ = 2181069520.

The previous prime is 2181238739. The next prime is 2181238777. The reversal of 2181238747 is 7478321812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2181238747 - 2³ = 2181238739 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2181238777) 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, 63529 + ... + 91642.

It is an arithmetic number, because the mean of its divisors is an integer number (545351994).

Almost surely, 2^2181238747 is an apocalyptic number.

2181238747 is a deficient number, since it is larger than the sum of its proper divisors (169229).

2181238747 is a wasteful number, since it uses less digits than its factorization.

2181238747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169228.

The product of its digits is 150528, while the sum is 43.

The square root of 2181238747 is about 46703.7337586622. The cubic root of 2181238747 is about 1296.8838078326.

The spelling of 2181238747 in words is "two billion, one hundred eighty-one million, two hundred thirty-eight thousand, seven hundred forty-seven".