63761981 has 4 divisors (see below), whose sum is σ = 65960700. Its totient is φ = 61563264.

The previous prime is 63761977. The next prime is 63762059. The reversal of 63761981 is 18916736.

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 37332100 + 26429881 = 6110^2 + 5141^2 .

It is a cyclic number.

It is not a de Polignac number, because 63761981 - 2² = 63761977 is a prime.

It is a super-2 number, since 2×63761981² = 8131180442088722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63766981) 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, 1099316 + ... + 1099373.

It is an arithmetic number, because the mean of its divisors is an integer number (16490175).

Almost surely, 2^63761981 is an apocalyptic number.

It is an amenable number.

63761981 is a deficient number, since it is larger than the sum of its proper divisors (2198719).

63761981 is a wasteful number, since it uses less digits than its factorization.

63761981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2198718.

The product of its digits is 54432, while the sum is 41.

The square root of 63761981 is about 7985.1099554108. The cubic root of 63761981 is about 399.5035110852.

The spelling of 63761981 in words is "sixty-three million, seven hundred sixty-one thousand, nine hundred eighty-one".