20751040 has 56 divisors (see below), whose sum is σ = 52029360. Its totient is φ = 7861248.

The previous prime is 20751023. The next prime is 20751047. The reversal of 20751040 is 4015702.

It is a super-2 number, since 2×20751040² = 861211322163200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a junction number, because it is equal to n+sod(n) for n = 20750999 and 20751017.

It is not an unprimeable number, because it can be changed into a prime (20751047) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4374 + ... + 7786.

Almost surely, 2^20751040 is an apocalyptic number.

20751040 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 20751040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26014680).

20751040 is an abundant number, since it is smaller than the sum of its proper divisors (31278320).

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

20751040 is a wasteful number, since it uses less digits than its factorization.

20751040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3449 (or 3439 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 20751040 is about 4555.3309429722. The cubic root of 20751040 is about 274.7978238511.

Adding to 20751040 its reverse (4015702), we get a palindrome (24766742).

The spelling of 20751040 in words is "twenty million, seven hundred fifty-one thousand, forty".