20249640 has 48 divisors (see below), whose sum is σ = 65812500. Its totient is φ = 5399808.

The previous prime is 20249633. The next prime is 20249641. The reversal of 20249640 is 4694202.

It can be written as a sum of positive squares in 2 ways, for example, as 19554084 + 695556 = 4422^2 + 834^2 .

It is not an unprimeable number, because it can be changed into a prime (20249641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27765 + ... + 28484.

Almost surely, 2^20249640 is an apocalyptic number.

20249640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20249640 is an abundant number, since it is smaller than the sum of its proper divisors (45562860).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20249640 is a wasteful number, since it uses less digits than its factorization.

20249640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56266 (or 56259 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 20249640 is about 4499.9599998222. The cubic root of 20249640 is about 272.5664736969.

It can be divided in two parts, 2024 and 9640, that added together give a square (11664 = 108²).

The spelling of 20249640 in words is "twenty million, two hundred forty-nine thousand, six hundred forty".