639293071 has 4 divisors (see below), whose sum is σ = 639361144. Its totient is φ = 639225000.

The previous prime is 639292991. The next prime is 639293077. The reversal of 639293071 is 170392936.

639293071 = T₂₀₆₄₃ + T₂₀₆₄₄ + T₂₀₆₄₅.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 639293071 - 2¹³ = 639284879 is a prime.

It is a super-2 number, since 2×639293071² = 817391261257222082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639293077) 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, 17160 + ... + 39661.

It is an arithmetic number, because the mean of its divisors is an integer number (159840286).

Almost surely, 2^639293071 is an apocalyptic number.

639293071 is the 20645-th centered triangular number.

639293071 is a deficient number, since it is larger than the sum of its proper divisors (68073).

639293071 is a wasteful number, since it uses less digits than its factorization.

639293071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68072.

The product of its (nonzero) digits is 61236, while the sum is 40.

The square root of 639293071 is about 25284.2455098031. The cubic root of 639293071 is about 861.4564607057.

The spelling of 639293071 in words is "six hundred thirty-nine million, two hundred ninety-three thousand, seventy-one".