645923641 has 16 divisors (see below), whose sum is σ = 737164800. Its totient is φ = 560560000.

The previous prime is 645923633. The next prime is 645923711. The reversal of 645923641 is 146329546.

It is not a de Polignac number, because 645923641 - 2³ = 645923633 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645923594 and 645923603.

It is not an unprimeable number, because it can be changed into a prime (645923611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17016 + ... + 39766.

It is an arithmetic number, because the mean of its divisors is an integer number (46072800).

Almost surely, 2^645923641 is an apocalyptic number.

It is an amenable number.

645923641 is a deficient number, since it is larger than the sum of its proper divisors (91241159).

645923641 is a wasteful number, since it uses less digits than its factorization.

645923641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22880.

The product of its digits is 155520, while the sum is 40.

The square root of 645923641 is about 25415.0278575492. The cubic root of 645923641 is about 864.4244853630.

The spelling of 645923641 in words is "six hundred forty-five million, nine hundred twenty-three thousand, six hundred forty-one".