20781403 has 2 divisors, whose sum is σ = 20781404. Its totient is φ = 20781402.

The previous prime is 20781389. The next prime is 20781407. The reversal of 20781403 is 30418702.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20781403 - 2²¹ = 18684251 is a prime.

It is not a weakly prime, because it can be changed into another prime (20781407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10390701 + 10390702.

It is an arithmetic number, because the mean of its divisors is an integer number (10390702).

Almost surely, 2^20781403 is an apocalyptic number.

20781403 is a deficient number, since it is larger than the sum of its proper divisors (1).

20781403 is an equidigital number, since it uses as much as digits as its factorization.

20781403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 20781403 is about 4558.6624134717. The cubic root of 20781403 is about 274.9317869381.

It can be divided in two parts, 2078 and 1403, that added together give a square (3481 = 59²).

The spelling of 20781403 in words is "twenty million, seven hundred eighty-one thousand, four hundred three".