645347977 has 4 divisors (see below), whose sum is σ = 679313680. Its totient is φ = 611382276.

The previous prime is 645347957. The next prime is 645347993. The reversal of 645347977 is 779743546.

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.

It is a cyclic number.

It is not a de Polignac number, because 645347977 - 2⁷ = 645347849 is a prime.

It is a super-2 number, since 2×645347977² = 832948022835985058, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645347957) 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, 16982823 + ... + 16982860.

It is an arithmetic number, because the mean of its divisors is an integer number (169828420).

Almost surely, 2^645347977 is an apocalyptic number.

It is an amenable number.

645347977 is a deficient number, since it is larger than the sum of its proper divisors (33965703).

645347977 is a wasteful number, since it uses less digits than its factorization.

645347977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33965702.

The product of its digits is 4445280, while the sum is 52.

The square root of 645347977 is about 25403.7000651480. The cubic root of 645347977 is about 864.1676098189.

The spelling of 645347977 in words is "six hundred forty-five million, three hundred forty-seven thousand, nine hundred seventy-seven".