645406061 has 2 divisors, whose sum is σ = 645406062. Its totient is φ = 645406060.

The previous prime is 645406033. The next prime is 645406123. The reversal of 645406061 is 160604546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 342472036 + 302934025 = 18506^2 + 17405^2 .

It is a cyclic number.

It is not a de Polignac number, because 645406061 - 2⁶ = 645405997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645406001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322703030 + 322703031.

It is an arithmetic number, because the mean of its divisors is an integer number (322703031).

Almost surely, 2^645406061 is an apocalyptic number.

It is an amenable number.

645406061 is a deficient number, since it is larger than the sum of its proper divisors (1).

645406061 is an equidigital number, since it uses as much as digits as its factorization.

645406061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 645406061 is about 25404.8432587174. The cubic root of 645406061 is about 864.1935352666.

The spelling of 645406061 in words is "six hundred forty-five million, four hundred six thousand, sixty-one".