645454671 has 4 divisors (see below), whose sum is σ = 860606232. Its totient is φ = 430303112.

The previous prime is 645454669. The next prime is 645454721. The reversal of 645454671 is 176454546.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 645454671 - 2¹ = 645454669 is a prime.

It is a super-2 number, since 2×645454671² = 833223464631436482, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645454661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107575776 + ... + 107575781.

It is an arithmetic number, because the mean of its divisors is an integer number (215151558).

Almost surely, 2^645454671 is an apocalyptic number.

645454671 is a deficient number, since it is larger than the sum of its proper divisors (215151561).

645454671 is a wasteful number, since it uses less digits than its factorization.

645454671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215151560.

The product of its digits is 403200, while the sum is 42.

The square root of 645454671 is about 25405.7999480434. The cubic root of 645454671 is about 864.2152308552.

The spelling of 645454671 in words is "six hundred forty-five million, four hundred fifty-four thousand, six hundred seventy-one".