999623409 has 16 divisors (see below), whose sum is σ = 1434372480. Its totient is φ = 616930560.

The previous prime is 999623399. The next prime is 999623431. The reversal of 999623409 is 904326999.

It is not a de Polignac number, because 999623409 - 2⁷ = 999623281 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (999623479) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 157549 + ... + 163770.

It is an arithmetic number, because the mean of its divisors is an integer number (89648280).

Almost surely, 2^999623409 is an apocalyptic number.

It is an amenable number.

999623409 is a deficient number, since it is larger than the sum of its proper divisors (434749071).

999623409 is a wasteful number, since it uses less digits than its factorization.

999623409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321400.

The product of its (nonzero) digits is 944784, while the sum is 51.

The square root of 999623409 is about 31616.8216144507. The cubic root of 999623409 is about 999.8744539055.

The spelling of 999623409 in words is "nine hundred ninety-nine million, six hundred twenty-three thousand, four hundred nine".