21755612 has 6 divisors (see below), whose sum is σ = 38072328. Its totient is φ = 10877804.

The previous prime is 21755611. The next prime is 21755633. The reversal of 21755612 is 21655712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21755611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2719448 + ... + 2719455.

It is an arithmetic number, because the mean of its divisors is an integer number (6345388).

Almost surely, 2^21755612 is an apocalyptic number.

It is an amenable number.

21755612 is a deficient number, since it is larger than the sum of its proper divisors (16316716).

21755612 is a wasteful number, since it uses less digits than its factorization.

21755612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5438907 (or 5438905 counting only the distinct ones).

The product of its digits is 4200, while the sum is 29.

The square root of 21755612 is about 4664.2911572928. The cubic root of 21755612 is about 279.1625145691.

The spelling of 21755612 in words is "twenty-one million, seven hundred fifty-five thousand, six hundred twelve".