645632047 has 4 divisors (see below), whose sum is σ = 645763576. Its totient is φ = 645500520.

The previous prime is 645632023. The next prime is 645632081. The reversal of 645632047 is 740236546.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645632047 is a prime.

It is a super-2 number, since 2×645632047² = 833681480226820418, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645631997 and 645632015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645632947) 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, 58104 + ... + 68317.

It is an arithmetic number, because the mean of its divisors is an integer number (161440894).

Almost surely, 2^645632047 is an apocalyptic number.

645632047 is a deficient number, since it is larger than the sum of its proper divisors (131529).

645632047 is a wasteful number, since it uses less digits than its factorization.

645632047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131528.

The product of its (nonzero) digits is 120960, while the sum is 37.

The square root of 645632047 is about 25409.2905646734. The cubic root of 645632047 is about 864.2943879765.

It can be divided in two parts, 6456 and 32047, that added together give a triangular number (38503 = T₂₇₇).

The spelling of 645632047 in words is "six hundred forty-five million, six hundred thirty-two thousand, forty-seven".