63440781 has 8 divisors (see below), whose sum is σ = 86555040. Its totient is φ = 41310192.

The previous prime is 63440779. The next prime is 63440789. The reversal of 63440781 is 18704436.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 63440781 - 2¹ = 63440779 is a prime.

It is a super-2 number, since 2×63440781² = 8049465387779922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63440789) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 245766 + ... + 246023.

It is an arithmetic number, because the mean of its divisors is an integer number (10819380).

Almost surely, 2^63440781 is an apocalyptic number.

It is an amenable number.

63440781 is a deficient number, since it is larger than the sum of its proper divisors (23114259).

63440781 is a wasteful number, since it uses less digits than its factorization.

63440781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491835.

The product of its (nonzero) digits is 16128, while the sum is 33.

The square root of 63440781 is about 7964.9721280115. The cubic root of 63440781 is about 398.8315505548.

The spelling of 63440781 in words is "sixty-three million, four hundred forty thousand, seven hundred eighty-one".