20513545 has 8 divisors (see below), whose sum is σ = 26509896. Its totient is φ = 15148416.

The previous prime is 20513531. The next prime is 20513551. The reversal of 20513545 is 54531502.

It can be written as a sum of positive squares in 4 ways, for example, as 1669264 + 18844281 = 1292^2 + 4341^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20513545 - 2⁵ = 20513513 is a prime.

It is a super-3 number, since 3×20513545³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 157732 + ... + 157861.

It is an arithmetic number, because the mean of its divisors is an integer number (3313737).

Almost surely, 2^20513545 is an apocalyptic number.

It is an amenable number.

20513545 is a deficient number, since it is larger than the sum of its proper divisors (5996351).

20513545 is a wasteful number, since it uses less digits than its factorization.

20513545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315611.

The product of its (nonzero) digits is 3000, while the sum is 25.

The square root of 20513545 is about 4529.1881170912. The cubic root of 20513545 is about 273.7454479619.

The spelling of 20513545 in words is "twenty million, five hundred thirteen thousand, five hundred forty-five".