1621189697 has 8 divisors (see below), whose sum is σ = 1677550440. Its totient is φ = 1564859520.

The previous prime is 1621189663. The next prime is 1621189709. The reversal of 1621189697 is 7969811261.

It is a Cunningham number, because it is equal to 40264²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 185613376 + 1435576321 = 13624^2 + 37889^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1621189697 - 2⁸ = 1621189441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1621189607) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 172943 + ... + 182075.

It is an arithmetic number, because the mean of its divisors is an integer number (209693805).

Almost surely, 2^1621189697 is an apocalyptic number.

It is an amenable number.

1621189697 is a deficient number, since it is larger than the sum of its proper divisors (56360743).

1621189697 is an equidigital number, since it uses as much as digits as its factorization.

1621189697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15283.

The product of its digits is 326592, while the sum is 50.

The square root of 1621189697 is about 40264.0000124180. Note that the first 4 decimals coincide. The cubic root of 1621189697 is about 1174.7477223893.

The spelling of 1621189697 in words is "one billion, six hundred twenty-one million, one hundred eighty-nine thousand, six hundred ninety-seven".