21860040 has 32 divisors (see below), whose sum is σ = 65580480. Its totient is φ = 5829312.

The previous prime is 21859987. The next prime is 21860057. The reversal of 21860040 is 4006812.

It is a super-2 number, since 2×21860040² = 955722697603200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21859989 and 21860016.

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, 90964 + ... + 91203.

It is an arithmetic number, because the mean of its divisors is an integer number (2049390).

Almost surely, 2^21860040 is an apocalyptic number.

21860040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21860040 is an abundant number, since it is smaller than the sum of its proper divisors (43720440).

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

21860040 is a wasteful number, since it uses less digits than its factorization.

21860040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182181 (or 182177 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21860040 is about 4675.4721686692. The cubic root of 21860040 is about 279.6084663657.

Adding to 21860040 its reverse (4006812), we get a palindrome (25866852).

The spelling of 21860040 in words is "twenty-one million, eight hundred sixty thousand, forty".