21539822 has 12 divisors (see below), whose sum is σ = 33777240. Its totient is φ = 10301148.

The previous prime is 21539813. The next prime is 21539831. The reversal of 21539822 is 22893512.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21539813) and next prime (21539831).

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9122 + ... + 11237.

It is an arithmetic number, because the mean of its divisors is an integer number (2814770).

Almost surely, 2^21539822 is an apocalyptic number.

21539822 is a deficient number, since it is larger than the sum of its proper divisors (12237418).

21539822 is a wasteful number, since it uses less digits than its factorization.

21539822 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20407 (or 20384 counting only the distinct ones).

The product of its digits is 8640, while the sum is 32.

The square root of 21539822 is about 4641.1013779059. The cubic root of 21539822 is about 278.2364584118.

The spelling of 21539822 in words is "twenty-one million, five hundred thirty-nine thousand, eight hundred twenty-two".