1621073538 has 24 divisors (see below), whose sum is σ = 4014087168. Its totient is φ = 463163832.

The previous prime is 1621073537. The next prime is 1621073567. The reversal of 1621073538 is 8353701261.

1621073538 is a `hidden beast` number, since 16 + 2 + 107 + 3 + 538 = 666.

It is not an unprimeable number, because it can be changed into a prime (1621073537) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6432706 + ... + 6432957.

It is an arithmetic number, because the mean of its divisors is an integer number (167253632).

Almost surely, 2^1621073538 is an apocalyptic number.

1621073538 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1621073538 is an abundant number, since it is smaller than the sum of its proper divisors (2393013630).

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

1621073538 is a wasteful number, since it uses less digits than its factorization.

1621073538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12865678 (or 12865675 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 1621073538 is about 40262.5575193628. The cubic root of 1621073538 is about 1174.7196646445.

Adding to 1621073538 its reverse (8353701261), we get a palindrome (9974774799).

The spelling of 1621073538 in words is "one billion, six hundred twenty-one million, seventy-three thousand, five hundred thirty-eight".