661021206 has 16 divisors (see below), whose sum is σ = 1357773744. Its totient is φ = 214385184.

The previous prime is 661021199. The next prime is 661021211. The reversal of 661021206 is 602120166.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1488565 + ... + 1489008.

It is an arithmetic number, because the mean of its divisors is an integer number (84860859).

Almost surely, 2^661021206 is an apocalyptic number.

661021206 is an abundant number, since it is smaller than the sum of its proper divisors (696752538).

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

661021206 is a wasteful number, since it uses less digits than its factorization.

661021206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2977615.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 661021206 is about 25710.3326699598. The cubic root of 661021206 is about 871.1075892076.

The spelling of 661021206 in words is "six hundred sixty-one million, twenty-one thousand, two hundred six".