661610401323371 has 2 divisors, whose sum is σ = 661610401323372. Its totient is φ = 661610401323370.

The previous prime is 661610401323329. The next prime is 661610401323437. The reversal of 661610401323371 is 173323104016166.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661610401323371 is a prime.

It is a super-2 number, since 2×661610401323371² (a number of 30 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (661610401023371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330805200661685 + 330805200661686.

It is an arithmetic number, because the mean of its divisors is an integer number (330805200661686).

Almost surely, 2^{661610401323371} is an apocalyptic number.

661610401323371 is a deficient number, since it is larger than the sum of its proper divisors (1).

661610401323371 is an equidigital number, since it uses as much as digits as its factorization.

661610401323371 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 326592, while the sum is 44.

The spelling of 661610401323371 in words is "six hundred sixty-one trillion, six hundred ten billion, four hundred one million, three hundred twenty-three thousand, three hundred seventy-one".