90781820 has 12 divisors (see below), whose sum is σ = 190641864. Its totient is φ = 36312720.

The previous prime is 90781811. The next prime is 90781841. The reversal of 90781820 is 2818709.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2269526 + ... + 2269565.

It is an arithmetic number, because the mean of its divisors is an integer number (15886822).

Almost surely, 2^90781820 is an apocalyptic number.

It is an amenable number.

90781820 is an abundant number, since it is smaller than the sum of its proper divisors (99860044).

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

90781820 is a wasteful number, since it uses less digits than its factorization.

90781820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4539100 (or 4539098 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 90781820 is about 9527.9494121243. The cubic root of 90781820 is about 449.4343840115.

The spelling of 90781820 in words is "ninety million, seven hundred eighty-one thousand, eight hundred twenty".