661381363 has 2 divisors, whose sum is σ = 661381364. Its totient is φ = 661381362.

The previous prime is 661381351. The next prime is 661381367. The reversal of 661381363 is 363183166.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661381363 is a prime.

It is not a weakly prime, because it can be changed into another prime (661381367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330690681 + 330690682.

It is an arithmetic number, because the mean of its divisors is an integer number (330690682).

Almost surely, 2^661381363 is an apocalyptic number.

661381363 is a deficient number, since it is larger than the sum of its proper divisors (1).

661381363 is an equidigital number, since it uses as much as digits as its factorization.

661381363 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 37.

The square root of 661381363 is about 25717.3358456898. The cubic root of 661381363 is about 871.2657679624.

The spelling of 661381363 in words is "six hundred sixty-one million, three hundred eighty-one thousand, three hundred sixty-three".