209440390 has 16 divisors (see below), whose sum is σ = 377179920. Its totient is φ = 83734560.

The previous prime is 209440373. The next prime is 209440393. The reversal of 209440390 is 93044902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209440393) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23476 + ... + 31144.

It is an arithmetic number, because the mean of its divisors is an integer number (23573745).

Almost surely, 2^209440390 is an apocalyptic number.

209440390 is a deficient number, since it is larger than the sum of its proper divisors (167739530).

209440390 is a wasteful number, since it uses less digits than its factorization.

209440390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10407.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 209440390 is about 14472.0554863502. The cubic root of 209440390 is about 593.8637449305.

The spelling of 209440390 in words is "two hundred nine million, four hundred forty thousand, three hundred ninety".