639054551 has 4 divisors (see below), whose sum is σ = 639563400. Its totient is φ = 638545704.

The previous prime is 639054511. The next prime is 639054557. The reversal of 639054551 is 155450936.

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

It is a cyclic number.

It is not a de Polignac number, because 639054551 - 2⁶ = 639054487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639054557) 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, 252536 + ... + 255053.

It is an arithmetic number, because the mean of its divisors is an integer number (159890850).

Almost surely, 2^639054551 is an apocalyptic number.

639054551 is a deficient number, since it is larger than the sum of its proper divisors (508849).

639054551 is a wasteful number, since it uses less digits than its factorization.

639054551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 508848.

The product of its (nonzero) digits is 81000, while the sum is 38.

The square root of 639054551 is about 25279.5282986056. The cubic root of 639054551 is about 861.3493110202.

The spelling of 639054551 in words is "six hundred thirty-nine million, fifty-four thousand, five hundred fifty-one".