21346620 has 24 divisors (see below), whose sum is σ = 59770704. Its totient is φ = 5692416.

The previous prime is 21346573. The next prime is 21346621. The reversal of 21346620 is 2664312.

21346620 = 1630² + 1631² + ... + 1637².

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21346621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 177829 + ... + 177948.

It is an arithmetic number, because the mean of its divisors is an integer number (2490446).

Almost surely, 2^21346620 is an apocalyptic number.

21346620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21346620 is an abundant number, since it is smaller than the sum of its proper divisors (38424084).

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

21346620 is a wasteful number, since it uses less digits than its factorization.

21346620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355789 (or 355787 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 24.

The square root of 21346620 is about 4620.2402534933. The cubic root of 21346620 is about 277.4020756668.

It can be divided in two parts, 21 and 346620, that multiplied together give a triangular number (7279020 = T₃₈₁₅).

The spelling of 21346620 in words is "twenty-one million, three hundred forty-six thousand, six hundred twenty".