21085270 has 32 divisors (see below), whose sum is σ = 41492736. Its totient is φ = 7680000.

The previous prime is 21085261. The next prime is 21085271. The reversal of 21085270 is 7258012.

21085270 = 523² + 524² + ... + 590².

It is a super-2 number, since 2×21085270² = 889177221945800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21085271) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3270 + ... + 7270.

It is an arithmetic number, because the mean of its divisors is an integer number (1296648).

Almost surely, 2^21085270 is an apocalyptic number.

21085270 is a deficient number, since it is larger than the sum of its proper divisors (20407466).

21085270 is a wasteful number, since it uses less digits than its factorization.

21085270 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4056.

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 21085270 is about 4591.8699894487. The cubic root of 21085270 is about 276.2653315543.

The spelling of 21085270 in words is "twenty-one million, eighty-five thousand, two hundred seventy".