20771780 has 12 divisors (see below), whose sum is σ = 43620780. Its totient is φ = 8308704.

The previous prime is 20771747. The next prime is 20771797. The reversal of 20771780 is 8717702.

It can be written as a sum of positive squares in 2 ways, for example, as 8479744 + 12292036 = 2912^2 + 3506^2 .

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, 519275 + ... + 519314.

It is an arithmetic number, because the mean of its divisors is an integer number (3635065).

Almost surely, 2^20771780 is an apocalyptic number.

20771780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20771780 is an abundant number, since it is smaller than the sum of its proper divisors (22849000).

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

20771780 is a wasteful number, since it uses less digits than its factorization.

20771780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1038598 (or 1038596 counting only the distinct ones).

The product of its (nonzero) digits is 5488, while the sum is 32.

The square root of 20771780 is about 4557.6068281501. The cubic root of 20771780 is about 274.8893439093.

The spelling of 20771780 in words is "twenty million, seven hundred seventy-one thousand, seven hundred eighty".