20690740 has 72 divisors (see below), whose sum is σ = 51825312. Its totient is φ = 6914880.

The previous prime is 20690737. The next prime is 20690767. The reversal of 20690740 is 4709602.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 20690699 and 20690708.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41895 + ... + 42385.

It is an arithmetic number, because the mean of its divisors is an integer number (719796).

Almost surely, 2^20690740 is an apocalyptic number.

20690740 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 20690740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25912656).

20690740 is an abundant number, since it is smaller than the sum of its proper divisors (31134572).

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

20690740 is a wasteful number, since it uses less digits than its factorization.

20690740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 557 (or 548 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 20690740 is about 4548.7075087326. The cubic root of 20690740 is about 274.5313892504.

The spelling of 20690740 in words is "twenty million, six hundred ninety thousand, seven hundred forty".