1621505150021 has 16 divisors (see below), whose sum is σ = 1644265623600. Its totient is φ = 1598848204800.

The previous prime is 1621505149991. The next prime is 1621505150053. The reversal of 1621505150021 is 1200515051261.

It can be written as a sum of positive squares in 8 ways, for example, as 39318527521 + 1582186622500 = 198289^2 + 1257850^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621505150021 - 2¹⁴ = 1621505133637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621505150081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 163107911 + ... + 163117851.

It is an arithmetic number, because the mean of its divisors is an integer number (102766601475).

Almost surely, 2^{1621505150021} is an apocalyptic number.

It is an amenable number.

1621505150021 is a deficient number, since it is larger than the sum of its proper divisors (22760473579).

1621505150021 is an equidigital number, since it uses as much as digits as its factorization.

1621505150021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14920.

The product of its (nonzero) digits is 3000, while the sum is 29.

The spelling of 1621505150021 in words is "one trillion, six hundred twenty-one billion, five hundred five million, one hundred fifty thousand, twenty-one".