1401811638 has 16 divisors (see below), whose sum is σ = 2807278320. Its totient is φ = 466661376.

The previous prime is 1401811633. The next prime is 1401811667. The reversal of 1401811638 is 8361181041.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1401811599 and 1401811608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1401811633) 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, 147295 + ... + 156522.

It is an arithmetic number, because the mean of its divisors is an integer number (175454895).

Almost surely, 2^1401811638 is an apocalyptic number.

1401811638 is an abundant number, since it is smaller than the sum of its proper divisors (1405466682).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1401811638 is a wasteful number, since it uses less digits than its factorization.

1401811638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304591.

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 1401811638 is about 37440.7750721055. The cubic root of 1401811638 is about 1119.1712720437.

Adding to 1401811638 its reverse (8361181041), we get a palindrome (9762992679).

The spelling of 1401811638 in words is "one billion, four hundred one million, eight hundred eleven thousand, six hundred thirty-eight".