20891345 has 16 divisors (see below), whose sum is σ = 25961040. Its totient is φ = 16128000.

The previous prime is 20891333. The next prime is 20891401. The reversal of 20891345 is 54319802.

It can be written as a sum of positive squares in 8 ways, for example, as 524176 + 20367169 = 724^2 + 4513^2 .

It is not a de Polignac number, because 20891345 - 2¹² = 20887249 is a prime.

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, 20201 + ... + 21209.

It is an arithmetic number, because the mean of its divisors is an integer number (1622565).

Almost surely, 2^20891345 is an apocalyptic number.

It is an amenable number.

20891345 is a deficient number, since it is larger than the sum of its proper divisors (5069695).

20891345 is a wasteful number, since it uses less digits than its factorization.

20891345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1156.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 20891345 is about 4570.7050878393. The cubic root of 20891345 is about 275.4157677852.

The spelling of 20891345 in words is "twenty million, eight hundred ninety-one thousand, three hundred forty-five".