63720913 has 4 divisors (see below), whose sum is σ = 67469220. Its totient is φ = 59972608.

The previous prime is 63720911. The next prime is 63720931. The reversal of 63720913 is 31902736.

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

It can be written as a sum of positive squares in 2 ways, for example, as 30162064 + 33558849 = 5492^2 + 5793^2 .

It is a cyclic number.

It is not a de Polignac number, because 63720913 - 2¹ = 63720911 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63720911) 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, 1874128 + ... + 1874161.

It is an arithmetic number, because the mean of its divisors is an integer number (16867305).

Almost surely, 2^63720913 is an apocalyptic number.

It is an amenable number.

63720913 is a deficient number, since it is larger than the sum of its proper divisors (3748307).

63720913 is a wasteful number, since it uses less digits than its factorization.

63720913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3748306.

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 63720913 is about 7982.5380049205. The cubic root of 63720913 is about 399.4177215408.

The spelling of 63720913 in words is "sixty-three million, seven hundred twenty thousand, nine hundred thirteen".