999961506 has 12 divisors (see below), whose sum is σ = 2166583302. Its totient is φ = 333320496.

The previous prime is 999961477. The next prime is 999961511. The reversal of 999961506 is 605169999.

It can be written as a sum of positive squares in only one way, i.e., 821338281 + 178623225 = 28659^2 + 13365^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 27776691 + ... + 27776726.

Almost surely, 2^999961506 is an apocalyptic number.

999961506 is an abundant number, since it is smaller than the sum of its proper divisors (1166621796).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999961506 is a wasteful number, since it uses less digits than its factorization.

999961506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55553425 (or 55553422 counting only the distinct ones).

The product of its (nonzero) digits is 1180980, while the sum is 54.

The square root of 999961506 is about 31622.1679522451. The cubic root of 999961506 is about 999.9871685020.

Adding to 999961506 its sum of digits (54), we get a triangular number (999961560 = T₄₄₇₂₀).

The spelling of 999961506 in words is "nine hundred ninety-nine million, nine hundred sixty-one thousand, five hundred six".