1621221402 has 16 divisors (see below), whose sum is σ = 3252068352. Its totient is φ = 538802880.

The previous prime is 1621221361. The next prime is 1621221409. The reversal of 1621221402 is 2041221261.

It is not an unprimeable number, because it can be changed into a prime (1621221409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 398874 + ... + 402917.

It is an arithmetic number, because the mean of its divisors is an integer number (203254272).

Almost surely, 2^1621221402 is an apocalyptic number.

1621221402 is an abundant number, since it is smaller than the sum of its proper divisors (1630846950).

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

1621221402 is a wasteful number, since it uses less digits than its factorization.

1621221402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 802133.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 1621221402 is about 40264.3937244807. The cubic root of 1621221402 is about 1174.7553803731.

Adding to 1621221402 its reverse (2041221261), we get a palindrome (3662442663).

The spelling of 1621221402 in words is "one billion, six hundred twenty-one million, two hundred twenty-one thousand, four hundred two".