20378491 has 16 divisors (see below), whose sum is σ = 23874048. Its totient is φ = 17035200.

The previous prime is 20378489. The next prime is 20378497. The reversal of 20378491 is 19487302.

20378491 = T₄₉₁ + T₄₉₂ + ... + T₆₂₁.

It is not a de Polignac number, because 20378491 - 2¹ = 20378489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20378497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64951 + ... + 65263.

It is an arithmetic number, because the mean of its divisors is an integer number (1492128).

Almost surely, 2^20378491 is an apocalyptic number.

20378491 is a deficient number, since it is larger than the sum of its proper divisors (3495557).

20378491 is a wasteful number, since it uses less digits than its factorization.

20378491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 522.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 20378491 is about 4514.2542019696. The cubic root of 20378491 is about 273.1433766765.

The spelling of 20378491 in words is "twenty million, three hundred seventy-eight thousand, four hundred ninety-one".