210999969 has 24 divisors (see below), whose sum is σ = 317177640. Its totient is φ = 135002112.

The previous prime is 210999961. The next prime is 210999973. The reversal of 210999969 is 969999012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 136609344 + 74390625 = 11688^2 + 8625^2 .

It is not a de Polignac number, because 210999969 - 2³ = 210999961 is a prime.

It is a super-2 number, since 2×210999969² = 89041973836001922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (210999961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42817 + ... + 47489.

It is an arithmetic number, because the mean of its divisors is an integer number (13215735).

Almost surely, 2^210999969 is an apocalyptic number.

210999969 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

210999969 is a deficient number, since it is larger than the sum of its proper divisors (106177671).

210999969 is a wasteful number, since it uses less digits than its factorization.

210999969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4881 (or 4878 counting only the distinct ones).

The product of its (nonzero) digits is 708588, while the sum is 54.

The square root of 210999969 is about 14525.8379792699. The cubic root of 210999969 is about 595.3341521585.

The spelling of 210999969 in words is "two hundred ten million, nine hundred ninety-nine thousand, nine hundred sixty-nine".