21414540 has 96 divisors (see below), whose sum is σ = 69640704. Its totient is φ = 4815360.

The previous prime is 21414529. The next prime is 21414551. The reversal of 21414540 is 4541412.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21414529) and next prime (21414551).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 27760 + ... + 28520.

It is an arithmetic number, because the mean of its divisors is an integer number (725424).

Almost surely, 2^21414540 is an apocalyptic number.

21414540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21414540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34820352).

21414540 is an abundant number, since it is smaller than the sum of its proper divisors (48226164).

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

21414540 is a wasteful number, since it uses less digits than its factorization.

21414540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 847 (or 845 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 21.

The square root of 21414540 is about 4627.5846831798. The cubic root of 21414540 is about 277.6959738968.

Adding to 21414540 its reverse (4541412), we get a palindrome (25955952).

It can be divided in two parts, 214145 and 40, that added together give a triangular number (214185 = T₆₅₄).

The spelling of 21414540 in words is "twenty-one million, four hundred fourteen thousand, five hundred forty".