900639 has 10 divisors (see below), whose sum is σ = 1345520. Its totient is φ = 600372.

The previous prime is 900623. The next prime is 900649. The reversal of 900639 is 936009.

It is not a de Polignac number, because 900639 - 2⁴ = 900623 is a prime.

It is a super-2 number, since 2×900639² = 1622301216642, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (900649) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 5479 + ... + 5640.

It is an arithmetic number, because the mean of its divisors is an integer number (134552).

2⁹⁰⁰⁶³⁹ is an apocalyptic number.

900639 is a deficient number, since it is larger than the sum of its proper divisors (444881).

900639 is a wasteful number, since it uses less digits than its factorization.

900639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11131 (or 11122 counting only the distinct ones).

The product of its (nonzero) digits is 1458, while the sum is 27.

The square root of 900639 is about 949.0200208636. The cubic root of 900639 is about 96.5717829703.

It can be divided in two parts, 9006 and 39, that added together give a triangular number (9045 = T₁₃₄).

The spelling of 900639 in words is "nine hundred thousand, six hundred thirty-nine".