1401891787 has 4 divisors (see below), whose sum is σ = 1402319776. Its totient is φ = 1401463800.

The previous prime is 1401891773. The next prime is 1401891793. The reversal of 1401891787 is 7871981041.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1401891787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1401891707) 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, 209043 + ... + 215644.

It is an arithmetic number, because the mean of its divisors is an integer number (350579944).

Almost surely, 2^1401891787 is an apocalyptic number.

1401891787 is a deficient number, since it is larger than the sum of its proper divisors (427989).

1401891787 is an equidigital number, since it uses as much as digits as its factorization.

1401891787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427988.

The product of its (nonzero) digits is 112896, while the sum is 46.

The square root of 1401891787 is about 37441.8454005675. The cubic root of 1401891787 is about 1119.1926012880.

The spelling of 1401891787 in words is "one billion, four hundred one million, eight hundred ninety-one thousand, seven hundred eighty-seven".