209780977406 has 96 divisors (see below), whose sum is σ = 448102663680. Its totient is φ = 71474736960.

The previous prime is 209780977391. The next prime is 209780977409. The reversal of 209780977406 is 604779087902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209780977409) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 167735 + ... + 669101.

It is an arithmetic number, because the mean of its divisors is an integer number (4667736080).

Almost surely, 2^209780977406 is an apocalyptic number.

209780977406 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

209780977406 is an abundant number, since it is smaller than the sum of its proper divisors (238321686274).

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

209780977406 is a wasteful number, since it uses less digits than its factorization.

209780977406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501430 (or 501419 counting only the distinct ones).

The product of its (nonzero) digits is 10668672, while the sum is 59.

The spelling of 209780977406 in words is "two hundred nine billion, seven hundred eighty million, nine hundred seventy-seven thousand, four hundred six".