20751390 has 160 divisors (see below), whose sum is σ = 64921824. Its totient is φ = 4700160.

The previous prime is 20751361. The next prime is 20751391. The reversal of 20751390 is 9315702.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20751391) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 151402 + ... + 151538.

Almost surely, 2^20751390 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20751390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32460912).

20751390 is an abundant number, since it is smaller than the sum of its proper divisors (44170434).

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

20751390 is a wasteful number, since it uses less digits than its factorization.

20751390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184 (or 175 counting only the distinct ones).

The product of its (nonzero) digits is 1890, while the sum is 27.

The square root of 20751390 is about 4555.3693593385. The cubic root of 20751390 is about 274.7993688130.

The spelling of 20751390 in words is "twenty million, seven hundred fifty-one thousand, three hundred ninety".