21379716 has 36 divisors (see below), whose sum is σ = 54214524. Its totient is φ = 7104000.

The previous prime is 21379703. The next prime is 21379741. The reversal of 21379716 is 61797312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16842816 + 4536900 = 4104^2 + 2130^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13696 + ... + 15176.

It is an arithmetic number, because the mean of its divisors is an integer number (1505959).

Almost surely, 2^21379716 is an apocalyptic number.

It is an amenable number.

21379716 is an abundant number, since it is smaller than the sum of its proper divisors (32834808).

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

21379716 is a wasteful number, since it uses less digits than its factorization.

21379716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1892 (or 1887 counting only the distinct ones).

The product of its digits is 15876, while the sum is 36.

The square root of 21379716 is about 4623.8204982460. The cubic root of 21379716 is about 277.5453639011.

The spelling of 21379716 in words is "twenty-one million, three hundred seventy-nine thousand, seven hundred sixteen".