21619740 has 48 divisors (see below), whose sum is σ = 60752160. Its totient is φ = 5744640.

The previous prime is 21619721. The next prime is 21619769. The reversal of 21619740 is 4791612.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21619698 and 21619707.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24100 + ... + 24980.

It is an arithmetic number, because the mean of its divisors is an integer number (1265670).

Almost surely, 2^21619740 is an apocalyptic number.

21619740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21619740 is an abundant number, since it is smaller than the sum of its proper divisors (39132420).

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

21619740 is a wasteful number, since it uses less digits than its factorization.

21619740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1302 (or 1300 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 21619740 is about 4649.7032163354. The cubic root of 21619740 is about 278.5801421150.

The spelling of 21619740 in words is "twenty-one million, six hundred nineteen thousand, seven hundred forty".