20516240 has 40 divisors (see below), whose sum is σ = 47909880. Its totient is φ = 8170496.

The previous prime is 20516239. The next prime is 20516267. The reversal of 20516240 is 4261502.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1401856 + 19114384 = 1184^2 + 4372^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×20516240² = 841832207475200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

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, 24956 + ... + 25764.

It is an arithmetic number, because the mean of its divisors is an integer number (1197747).

Almost surely, 2^20516240 is an apocalyptic number.

20516240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20516240 is an abundant number, since it is smaller than the sum of its proper divisors (27393640).

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

20516240 is a wasteful number, since it uses less digits than its factorization.

20516240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1139 (or 1133 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 20516240 is about 4529.4856220105. The cubic root of 20516240 is about 273.7574353533.

Adding to 20516240 its reverse (4261502), we get a palindrome (24777742).

The spelling of 20516240 in words is "twenty million, five hundred sixteen thousand, two hundred forty".