63407991 has 4 divisors (see below), whose sum is σ = 84543992. Its totient is φ = 42271992.

The previous prime is 63407957. The next prime is 63407999. The reversal of 63407991 is 19970436.

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

It is not a de Polignac number, because 63407991 - 2⁷ = 63407863 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 (63407999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10567996 + ... + 10568001.

It is an arithmetic number, because the mean of its divisors is an integer number (21135998).

Almost surely, 2^63407991 is an apocalyptic number.

63407991 is a deficient number, since it is larger than the sum of its proper divisors (21136001).

63407991 is a wasteful number, since it uses less digits than its factorization.

63407991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21136000.

The product of its (nonzero) digits is 40824, while the sum is 39.

The square root of 63407991 is about 7962.9134743510. The cubic root of 63407991 is about 398.7628253590.

The spelling of 63407991 in words is "sixty-three million, four hundred seven thousand, nine hundred ninety-one".