21085386 has 24 divisors (see below), whose sum is σ = 49056480. Its totient is φ = 6024312.

The previous prime is 21085381. The next prime is 21085409. The reversal of 21085386 is 68358012.

It is a happy number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21085381) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35566 + ... + 36153.

It is an arithmetic number, because the mean of its divisors is an integer number (2044020).

Almost surely, 2^21085386 is an apocalyptic number.

21085386 is an abundant number, since it is smaller than the sum of its proper divisors (27971094).

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

21085386 is a wasteful number, since it uses less digits than its factorization.

21085386 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71738 (or 71731 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 21085386 is about 4591.8826204510. The cubic root of 21085386 is about 276.2658381752.

The spelling of 21085386 in words is "twenty-one million, eighty-five thousand, three hundred eighty-six".