645722542 has 4 divisors (see below), whose sum is σ = 968583816. Its totient is φ = 322861270.

The previous prime is 645722531. The next prime is 645722549. The reversal of 645722542 is 245227546.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645722549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161430634 + ... + 161430637.

It is an arithmetic number, because the mean of its divisors is an integer number (242145954).

Almost surely, 2^645722542 is an apocalyptic number.

645722542 is a deficient number, since it is larger than the sum of its proper divisors (322861274).

645722542 is a wasteful number, since it uses less digits than its factorization.

645722542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322861273.

The product of its digits is 134400, while the sum is 37.

The square root of 645722542 is about 25411.0712485719. The cubic root of 645722542 is about 864.3347673572.

The spelling of 645722542 in words is "six hundred forty-five million, seven hundred twenty-two thousand, five hundred forty-two".