645069077 has 4 divisors (see below), whose sum is σ = 649026720. Its totient is φ = 641111436.

The previous prime is 645069071. The next prime is 645069091. The reversal of 645069077 is 770960546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 770960546 = 2 ⋅385480273.

It is a cyclic number.

It is not a de Polignac number, because 645069077 - 2²⁶ = 577960213 is a prime.

It is a super-2 number, since 2×645069077² = 832228228203263858, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645069071) 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, 1978577 + ... + 1978902.

It is an arithmetic number, because the mean of its divisors is an integer number (162256680).

Almost surely, 2^645069077 is an apocalyptic number.

It is an amenable number.

645069077 is a deficient number, since it is larger than the sum of its proper divisors (3957643).

645069077 is a wasteful number, since it uses less digits than its factorization.

645069077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3957642.

The product of its (nonzero) digits is 317520, while the sum is 44.

The square root of 645069077 is about 25398.2101141006. The cubic root of 645069077 is about 864.0431027915.

The spelling of 645069077 in words is "six hundred forty-five million, sixty-nine thousand, seventy-seven".