65021661 has 24 divisors (see below), whose sum is σ = 96096000. Its totient is φ = 42355872.

The previous prime is 65021647. The next prime is 65021689. The reversal of 65021661 is 16612056.

It is a happy number.

65021661 is a `hidden beast` number, since 650 + 2 + 1 + 6 + 6 + 1 = 666.

It is not a de Polignac number, because 65021661 - 2¹⁹ = 64497373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65021261) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 77080 + ... + 77918.

It is an arithmetic number, because the mean of its divisors is an integer number (4004000).

Almost surely, 2^65021661 is an apocalyptic number.

It is an amenable number.

65021661 is a deficient number, since it is larger than the sum of its proper divisors (31074339).

65021661 is a wasteful number, since it uses less digits than its factorization.

65021661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1033 (or 1030 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 65021661 is about 8063.6009945929. The cubic root of 65021661 is about 402.1172339451.

The spelling of 65021661 in words is "sixty-five million, twenty-one thousand, six hundred sixty-one".