21435972 has 12 divisors (see below), whose sum is σ = 50017296. Its totient is φ = 7145320.

The previous prime is 21435961. The next prime is 21435983. The reversal of 21435972 is 27953412.

It is an interprime number because it is at equal distance from previous prime (21435961) and next prime (21435983).

It is a tau number, because it is divible by the number of its divisors (12).

It is a plaindrome in base 11.

It is a zygodrome in base 11.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 893154 + ... + 893177.

It is an arithmetic number, because the mean of its divisors is an integer number (4168108).

Almost surely, 2^21435972 is an apocalyptic number.

It is an amenable number.

21435972 is an abundant number, since it is smaller than the sum of its proper divisors (28581324).

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

21435972 is a wasteful number, since it uses less digits than its factorization.

21435972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1786338 (or 1786336 counting only the distinct ones).

The product of its digits is 15120, while the sum is 33.

The square root of 21435972 is about 4629.8997829327. The cubic root of 21435972 is about 277.7885838048.

The spelling of 21435972 in words is "twenty-one million, four hundred thirty-five thousand, nine hundred seventy-two".