65503981 has 2 divisors, whose sum is σ = 65503982. Its totient is φ = 65503980.

The previous prime is 65503979. The next prime is 65503993. The reversal of 65503981 is 18930556.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52794756 + 12709225 = 7266^2 + 3565^2 .

It is a cyclic number.

It is not a de Polignac number, because 65503981 - 2¹ = 65503979 is a prime.

It is a super-2 number, since 2×65503981² = 8581543053696722, which contains 22 as substring.

Together with 65503979, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 65503981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65503901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32751990 + 32751991.

It is an arithmetic number, because the mean of its divisors is an integer number (32751991).

Almost surely, 2^65503981 is an apocalyptic number.

It is an amenable number.

65503981 is a deficient number, since it is larger than the sum of its proper divisors (1).

65503981 is an equidigital number, since it uses as much as digits as its factorization.

65503981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32400, while the sum is 37.

The square root of 65503981 is about 8093.4529713837. The cubic root of 65503981 is about 403.1090654199.

The spelling of 65503981 in words is "sixty-five million, five hundred three thousand, nine hundred eighty-one".