21357210 has 32 divisors (see below), whose sum is σ = 58580352. Its totient is φ = 4881600.

The previous prime is 21357199. The next prime is 21357247. The reversal of 21357210 is 1275312.

It is a super-2 number, since 2×21357210² = 912260837968200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50641 + ... + 51060.

It is an arithmetic number, because the mean of its divisors is an integer number (1830636).

Almost surely, 2^21357210 is an apocalyptic number.

21357210 is an abundant number, since it is smaller than the sum of its proper divisors (37223142).

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

21357210 is a wasteful number, since it uses less digits than its factorization.

21357210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101718.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 21357210 is about 4621.3861556897. The cubic root of 21357210 is about 277.4479408877.

The spelling of 21357210 in words is "twenty-one million, three hundred fifty-seven thousand, two hundred ten".