20001540 has 48 divisors (see below), whose sum is σ = 60314688. Its totient is φ = 4923264.

The previous prime is 20001521. The next prime is 20001551. The reversal of 20001540 is 4510002.

20001540 = T₂₅₅ + T₂₅₆ + ... + T₅₁₄.

It is a Harshad number since it is a multiple of its sum of digits (12).

20001540 is a modest number, since divided by 1540 gives 20 as remainder.

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, 12042 + ... + 13601.

It is an arithmetic number, because the mean of its divisors is an integer number (1256556).

Almost surely, 2^20001540 is an apocalyptic number.

20001540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20001540 is an abundant number, since it is smaller than the sum of its proper divisors (40313148).

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

20001540 is a wasteful number, since it uses less digits than its factorization.

20001540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25668 (or 25666 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 12.

The square root of 20001540 is about 4472.3081289196. The cubic root of 20001540 is about 271.4487284859.

Adding to 20001540 its reverse (4510002), we get a palindrome (24511542).

The spelling of 20001540 in words is "twenty million, one thousand, five hundred forty".