20520690 has 64 divisors (see below), whose sum is σ = 51667200. Its totient is φ = 5209344.

The previous prime is 20520677. The next prime is 20520691. The reversal of 20520690 is 9602502.

It is a super-2 number, since 2×20520690² = 842197436152200, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20520690.

It is not an unprimeable number, because it can be changed into a prime (20520691) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 89496 + ... + 89724.

It is an arithmetic number, because the mean of its divisors is an integer number (807300).

Almost surely, 2^20520690 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20520690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25833600).

20520690 is an abundant number, since it is smaller than the sum of its proper divisors (31146510).

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

20520690 is a wasteful number, since it uses less digits than its factorization.

20520690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 371.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 20520690 is about 4529.9768211328. The cubic root of 20520690 is about 273.7772267076. Note that the first 3 decimals are identical.

It can be divided in two parts, 20 and 520690, that added together give a triangular number (520710 = T₁₀₂₀).

The spelling of 20520690 in words is "twenty million, five hundred twenty thousand, six hundred ninety".