21819902 has 8 divisors (see below), whose sum is σ = 35247576. Its totient is φ = 10070712.

The previous prime is 21819901. The next prime is 21819907. The reversal of 21819902 is 20991812.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21819902² = 952216246579208, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21819901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 419588 + ... + 419639.

It is an arithmetic number, because the mean of its divisors is an integer number (4405947).

Almost surely, 2^21819902 is an apocalyptic number.

21819902 is a deficient number, since it is larger than the sum of its proper divisors (13427674).

21819902 is a wasteful number, since it uses less digits than its factorization.

21819902 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 839242.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 21819902 is about 4671.1777958027. The cubic root of 21819902 is about 279.4372284879.

The spelling of 21819902 in words is "twenty-one million, eight hundred nineteen thousand, nine hundred two".