21156770 has 8 divisors (see below), whose sum is σ = 38082204. Its totient is φ = 8462704.

The previous prime is 21156769. The next prime is 21156809. The reversal of 21156770 is 7765112.

It can be written as a sum of positive squares in 2 ways, for example, as 21003889 + 152881 = 4583^2 + 391^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1057829 + ... + 1057848.

Almost surely, 2^21156770 is an apocalyptic number.

21156770 is a deficient number, since it is larger than the sum of its proper divisors (16925434).

21156770 is a wasteful number, since it uses less digits than its factorization.

21156770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2115684.

The product of its (nonzero) digits is 2940, while the sum is 29.

The square root of 21156770 is about 4599.6488996444. The cubic root of 21156770 is about 276.5772505033.

The spelling of 21156770 in words is "twenty-one million, one hundred fifty-six thousand, seven hundred seventy".