63721217 has 6 divisors (see below), whose sum is σ = 74124738. Its totient is φ = 54618144.

The previous prime is 63721187. The next prime is 63721249. The reversal of 63721217 is 71212736.

It can be written as a sum of positive squares in only one way, i.e., 54745201 + 8976016 = 7399^2 + 2996^2 .

It is not a de Polignac number, because 63721217 - 2⁶ = 63721153 is a prime.

It is a super-2 number, since 2×63721217² = 8120786991922178, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 63721217.

It is not an unprimeable number, because it can be changed into a prime (63721267) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 650168 + ... + 650265.

It is an arithmetic number, because the mean of its divisors is an integer number (12354123).

Almost surely, 2^63721217 is an apocalyptic number.

It is an amenable number.

63721217 is a deficient number, since it is larger than the sum of its proper divisors (10403521).

63721217 is a wasteful number, since it uses less digits than its factorization.

63721217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1300447 (or 1300440 counting only the distinct ones).

The product of its digits is 3528, while the sum is 29.

The square root of 63721217 is about 7982.5570464607. The cubic root of 63721217 is about 399.4183567210.

The spelling of 63721217 in words is "sixty-three million, seven hundred twenty-one thousand, two hundred seventeen".