21394761 has 16 divisors (see below), whose sum is σ = 29980800. Its totient is φ = 13544960.

The previous prime is 21394753. The next prime is 21394771. The reversal of 21394761 is 16749312.

It is a cyclic number.

It is not a de Polignac number, because 21394761 - 2³ = 21394753 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21394771) 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, 9241 + ... + 11321.

It is an arithmetic number, because the mean of its divisors is an integer number (1873800).

Almost surely, 2^21394761 is an apocalyptic number.

It is an amenable number.

21394761 is a deficient number, since it is larger than the sum of its proper divisors (8586039).

21394761 is a wasteful number, since it uses less digits than its factorization.

21394761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2256.

The product of its digits is 9072, while the sum is 33.

The square root of 21394761 is about 4625.4471135232. The cubic root of 21394761 is about 277.6104519328.

It can be divided in two parts, 21394 and 761, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 21394761 in words is "twenty-one million, three hundred ninety-four thousand, seven hundred sixty-one".