20778100 has 36 divisors (see below), whose sum is σ = 51531424. Its totient is φ = 7123680.

The previous prime is 20778083. The next prime is 20778113. The reversal of 20778100 is 187702.

It is a happy number.

It is a super-2 number, since 2×20778100² = 863458879220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14142 + ... + 15541.

Almost surely, 2^20778100 is an apocalyptic number.

20778100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20778100 is an abundant number, since it is smaller than the sum of its proper divisors (30753324).

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

20778100 is a wasteful number, since it uses less digits than its factorization.

20778100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29704 (or 29697 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 20778100 is about 4558.3001217559. The cubic root of 20778100 is about 274.9172202634.

The spelling of 20778100 in words is "twenty million, seven hundred seventy-eight thousand, one hundred".