21771150 has 48 divisors (see below), whose sum is σ = 56841600. Its totient is φ = 5499360.

The previous prime is 21771121. The next prime is 21771151. The reversal of 21771150 is 5117712.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21771150.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21771151) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 970 + ... + 6669.

It is an arithmetic number, because the mean of its divisors is an integer number (1184200).

Almost surely, 2^21771150 is an apocalyptic number.

21771150 is an abundant number, since it is smaller than the sum of its proper divisors (35070450).

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

21771150 is a wasteful number, since it uses less digits than its factorization.

21771150 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7673 (or 7668 counting only the distinct ones).

The product of its (nonzero) digits is 490, while the sum is 24.

The square root of 21771150 is about 4665.9564935820. The cubic root of 21771150 is about 279.2289586496.

Adding to 21771150 its reverse (5117712), we get a palindrome (26888862).

The spelling of 21771150 in words is "twenty-one million, seven hundred seventy-one thousand, one hundred fifty".