205401989 has 8 divisors (see below), whose sum is σ = 232844640. Its totient is φ = 179622576.

The previous prime is 205401979. The next prime is 205402003. The reversal of 205401989 is 989104502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205401989 is a prime.

It is a super-2 number, since 2×205401989² = 84379954170312242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205401929) 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, 415547 + ... + 416040.

It is an arithmetic number, because the mean of its divisors is an integer number (29105580).

Almost surely, 2^205401989 is an apocalyptic number.

It is an amenable number.

205401989 is a deficient number, since it is larger than the sum of its proper divisors (27442651).

205401989 is a wasteful number, since it uses less digits than its factorization.

205401989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 831619.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 205401989 is about 14331.8522529365. The cubic root of 205401989 is about 590.0220129678.

The spelling of 205401989 in words is "two hundred five million, four hundred one thousand, nine hundred eighty-nine".