999651 has 12 divisors (see below), whose sum is σ = 1417112. Its totient is φ = 626688.

The previous prime is 999631. The next prime is 999653. The reversal of 999651 is 156999.

999651 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 999651 - 2¹⁴ = 983267 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (999653) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 291 + ... + 1443.

2⁹⁹⁹⁶⁵¹ is an apocalyptic number.

999651 is a deficient number, since it is larger than the sum of its proper divisors (417461).

999651 is a wasteful number, since it uses less digits than its factorization.

999651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1190 (or 1173 counting only the distinct ones).

The product of its digits is 21870, while the sum is 39.

The square root of 999651 is about 999.8254847722. The cubic root of 999651 is about 99.9883653131.

It can be divided in two parts, 9996 and 51, that multiplied together give a square (509796 = 714²).

The spelling of 999651 in words is "nine hundred ninety-nine thousand, six hundred fifty-one".