21770580 has 144 divisors (see below), whose sum is σ = 70096320. Its totient is φ = 5031936.

The previous prime is 21770579. The next prime is 21770603. The reversal of 21770580 is 8507712.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 192604 + ... + 192716.

It is an arithmetic number, because the mean of its divisors is an integer number (486780).

Almost surely, 2^21770580 is an apocalyptic number.

21770580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21770580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35048160).

21770580 is an abundant number, since it is smaller than the sum of its proper divisors (48325740).

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

21770580 is a wasteful number, since it uses less digits than its factorization.

21770580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170 (or 155 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 30.

The square root of 21770580 is about 4665.8954124584. The cubic root of 21770580 is about 279.2265217565.

The spelling of 21770580 in words is "twenty-one million, seven hundred seventy thousand, five hundred eighty".