20687629 has 4 divisors (see below), whose sum is σ = 20738620. Its totient is φ = 20636640.

The previous prime is 20687627. The next prime is 20687659. The reversal of 20687629 is 92678602.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16826404 + 3861225 = 4102^2 + 1965^2 .

It is a cyclic number.

It is not a de Polignac number, because 20687629 - 2¹ = 20687627 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20687591 and 20687600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20687627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24882 + ... + 25699.

It is an arithmetic number, because the mean of its divisors is an integer number (5184655).

Almost surely, 2^20687629 is an apocalyptic number.

It is an amenable number.

20687629 is a deficient number, since it is larger than the sum of its proper divisors (50991).

20687629 is an equidigital number, since it uses as much as digits as its factorization.

20687629 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50990.

The product of its (nonzero) digits is 72576, while the sum is 40.

The square root of 20687629 is about 4548.3655306055. The cubic root of 20687629 is about 274.5176293114.

It can be divided in two parts, 20687 and 629, that added together give a square (21316 = 146²).

The spelling of 20687629 in words is "twenty million, six hundred eighty-seven thousand, six hundred twenty-nine".