3681506391 has 4 divisors (see below), whose sum is σ = 4908675192. Its totient is φ = 2454337592.

The previous prime is 3681506371. The next prime is 3681506461. The reversal of 3681506391 is 1936051863.

It is a happy number.

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 3681506391 - 2⁵ = 3681506359 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3681506321) 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, 613584396 + ... + 613584401.

It is an arithmetic number, because the mean of its divisors is an integer number (1227168798).

Almost surely, 2^3681506391 is an apocalyptic number.

3681506391 is a deficient number, since it is larger than the sum of its proper divisors (1227168801).

3681506391 is a wasteful number, since it uses less digits than its factorization.

3681506391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1227168800.

The product of its (nonzero) digits is 116640, while the sum is 42.

The square root of 3681506391 is about 60675.4183421919. The cubic root of 3681506391 is about 1544.0991583465.

The spelling of 3681506391 in words is "three billion, six hundred eighty-one million, five hundred six thousand, three hundred ninety-one".