63781901 has 4 divisors (see below), whose sum is σ = 63798204. Its totient is φ = 63765600.

The previous prime is 63781877. The next prime is 63781987. The reversal of 63781901 is 10918736.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 45549001 + 18232900 = 6749^2 + 4270^2 .

It is a cyclic number.

It is not a de Polignac number, because 63781901 - 2¹⁰ = 63780877 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 (63780901) 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, 1631 + ... + 11411.

It is an arithmetic number, because the mean of its divisors is an integer number (15949551).

It is a Poulet number, since it divides 2^63781900-1.

Almost surely, 2^63781901 is an apocalyptic number.

63781901 is the 6521-st pentagonal number.

It is an amenable number.

63781901 is a deficient number, since it is larger than the sum of its proper divisors (16303).

63781901 is an equidigital number, since it uses as much as digits as its factorization.

63781901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16302.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 63781901 is about 7986.3571795907. The cubic root of 63781901 is about 399.5451099671.

The spelling of 63781901 in words is "sixty-three million, seven hundred eighty-one thousand, nine hundred one".