1621746645 has 16 divisors (see below), whose sum is σ = 2595333312. Its totient is φ = 864752000.

The previous prime is 1621746563. The next prime is 1621746647. The reversal of 1621746645 is 5466471261.

It is not a de Polignac number, because 1621746645 - 2²² = 1617552341 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1621746597 and 1621746606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621746647) 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, 97294 + ... + 112736.

It is an arithmetic number, because the mean of its divisors is an integer number (162208332).

Almost surely, 2^1621746645 is an apocalyptic number.

1621746645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1621746645 is a deficient number, since it is larger than the sum of its proper divisors (973586667).

1621746645 is a wasteful number, since it uses less digits than its factorization.

1621746645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22452.

The product of its digits is 241920, while the sum is 42.

The square root of 1621746645 is about 40270.9156215748. The cubic root of 1621746645 is about 1174.8822323495.

The spelling of 1621746645 in words is "one billion, six hundred twenty-one million, seven hundred forty-six thousand, six hundred forty-five".