1621644266 has 16 divisors (see below), whose sum is σ = 2671178688. Its totient is φ = 732228000.

The previous prime is 1621644253. The next prime is 1621644293. The reversal of 1621644266 is 6624461261.

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, 240755 + ... + 247398.

It is an arithmetic number, because the mean of its divisors is an integer number (166948668).

Almost surely, 2^1621644266 is an apocalyptic number.

1621644266 is a deficient number, since it is larger than the sum of its proper divisors (1049534422).

1621644266 is a wasteful number, since it uses less digits than its factorization.

1621644266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488317.

The product of its digits is 82944, while the sum is 38.

The square root of 1621644266 is about 40269.6444732257. The cubic root of 1621644266 is about 1174.8575088413.

The spelling of 1621644266 in words is "one billion, six hundred twenty-one million, six hundred forty-four thousand, two hundred sixty-six".