1621557164 has 6 divisors (see below), whose sum is σ = 2837725044. Its totient is φ = 810778580.

The previous prime is 1621557149. The next prime is 1621557167. The reversal of 1621557164 is 4617551261.

It is a super-2 number, since 2×1621557164² = 5258895272239445792, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1621557167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 202694642 + ... + 202694649.

It is an arithmetic number, because the mean of its divisors is an integer number (472954174).

Almost surely, 2^1621557164 is an apocalyptic number.

It is an amenable number.

1621557164 is a deficient number, since it is larger than the sum of its proper divisors (1216167880).

1621557164 is a wasteful number, since it uses less digits than its factorization.

1621557164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 405389295 (or 405389293 counting only the distinct ones).

The product of its digits is 50400, while the sum is 38.

The square root of 1621557164 is about 40268.5629741117. The cubic root of 1621557164 is about 1174.8364737572.

The spelling of 1621557164 in words is "one billion, six hundred twenty-one million, five hundred fifty-seven thousand, one hundred sixty-four".