2638387821 has 8 divisors (see below), whose sum is σ = 3523324000. Its totient is φ = 1756188432.

The previous prime is 2638387819. The next prime is 2638387853. The reversal of 2638387821 is 1287838362.

2638387821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 2638387821 - 2¹ = 2638387819 is a prime.

It is a super-2 number, since 2×2638387821² = 13922180588002256082, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2638387621) 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, 681946 + ... + 685803.

It is an arithmetic number, because the mean of its divisors is an integer number (440415500).

Almost surely, 2^2638387821 is an apocalyptic number.

It is an amenable number.

2638387821 is a deficient number, since it is larger than the sum of its proper divisors (884936179).

2638387821 is a wasteful number, since it uses less digits than its factorization.

2638387821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1368395.

The product of its digits is 774144, while the sum is 48.

The square root of 2638387821 is about 51365.2394231741. The cubic root of 2638387821 is about 1381.8032543914.

The spelling of 2638387821 in words is "two billion, six hundred thirty-eight million, three hundred eighty-seven thousand, eight hundred twenty-one".