643973492 has 6 divisors (see below), whose sum is σ = 1126953618. Its totient is φ = 321986744.

The previous prime is 643973483. The next prime is 643973503. The reversal of 643973492 is 294379346.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 626701156 + 17272336 = 25034^2 + 4156^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80496683 + ... + 80496690.

It is an arithmetic number, because the mean of its divisors is an integer number (187825603).

Almost surely, 2^643973492 is an apocalyptic number.

It is an amenable number.

643973492 is a deficient number, since it is larger than the sum of its proper divisors (482980126).

643973492 is a wasteful number, since it uses less digits than its factorization.

643973492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160993377 (or 160993375 counting only the distinct ones).

The product of its digits is 979776, while the sum is 47.

The square root of 643973492 is about 25376.6327947583. The cubic root of 643973492 is about 863.5536621394.

The spelling of 643973492 in words is "six hundred forty-three million, nine hundred seventy-three thousand, four hundred ninety-two".