20995680 has 192 divisors, whose sum is σ = 73156608. Its totient is φ = 5038080.

The previous prime is 20995657. The next prime is 20995693. The reversal of 20995680 is 8659902.

20995680 = T₂₄₀ + T₂₄₁ + ... + T₅₁₈.

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 31 ways as a sum of consecutive naturals, for example, 252919 + ... + 253001.

It is an arithmetic number, because the mean of its divisors is an integer number (381024).

Almost surely, 2^20995680 is an apocalyptic number.

20995680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20995680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36578304).

20995680 is an abundant number, since it is smaller than the sum of its proper divisors (52160928).

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

20995680 is a wasteful number, since it uses less digits than its factorization.

20995680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149 (or 141 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 39.

The square root of 20995680 is about 4582.1043200695. The cubic root of 20995680 is about 275.8734980035.

The spelling of 20995680 in words is "twenty million, nine hundred ninety-five thousand, six hundred eighty".