20781474 has 32 divisors (see below), whose sum is σ = 47999616. Its totient is φ = 5875200.

The previous prime is 20781469. The next prime is 20781493. The reversal of 20781474 is 47418702.

It is a super-2 number, since 2×20781474² = 863739323225352, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1524 + ... + 6624.

It is an arithmetic number, because the mean of its divisors is an integer number (1499988).

Almost surely, 2^20781474 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20781474, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23999808).

20781474 is an abundant number, since it is smaller than the sum of its proper divisors (27218142).

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

20781474 is a wasteful number, since it uses less digits than its factorization.

20781474 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5210.

The product of its (nonzero) digits is 12544, while the sum is 33.

The square root of 20781474 is about 4558.6702008371. The cubic root of 20781474 is about 274.9321000407.

The spelling of 20781474 in words is "twenty million, seven hundred eighty-one thousand, four hundred seventy-four".