213121020 has 48 divisors (see below), whose sum is σ = 681988608. Its totient is φ = 48713280.

The previous prime is 213121019. The next prime is 213121021. The reversal of 213121020 is 20121312.

It is an interprime number because it is at equal distance from previous prime (213121019) and next prime (213121021).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 213120987 and 213121005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213121021) 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, 253296 + ... + 254135.

It is an arithmetic number, because the mean of its divisors is an integer number (14208096).

Almost surely, 2^213121020 is an apocalyptic number.

213121020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

213121020 is an abundant number, since it is smaller than the sum of its proper divisors (468867588).

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

213121020 is a wasteful number, since it uses less digits than its factorization.

213121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 507450 (or 507448 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 213121020 is about 14598.6650074587. The cubic root of 213121020 is about 597.3223458343.

Adding to 213121020 its reverse (20121312), we get a palindrome (233242332).

The spelling of 213121020 in words is "two hundred thirteen million, one hundred twenty-one thousand, twenty".