1621254121 has 8 divisors (see below), whose sum is σ = 1638124488. Its totient is φ = 1604400000.

The previous prime is 1621254073. The next prime is 1621254169. The reversal of 1621254121 is 1214521261.

It is an interprime number because it is at equal distance from previous prime (1621254073) and next prime (1621254169).

It can be written as a sum of positive squares in 4 ways, for example, as 583705600 + 1037548521 = 24160^2 + 32211^2 .

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 1621254121 - 2⁹ = 1621253609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1621254221) 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, 383821 + ... + 388021.

It is an arithmetic number, because the mean of its divisors is an integer number (204765561).

Almost surely, 2^1621254121 is an apocalyptic number.

It is an amenable number.

1621254121 is a deficient number, since it is larger than the sum of its proper divisors (16870367).

1621254121 is a wasteful number, since it uses less digits than its factorization.

1621254121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8123.

The product of its digits is 960, while the sum is 25.

The square root of 1621254121 is about 40264.8000243389. The cubic root of 1621254121 is about 1174.7632831726.

Adding to 1621254121 its reverse (1214521261), we get a palindrome (2835775382).

The spelling of 1621254121 in words is "one billion, six hundred twenty-one million, two hundred fifty-four thousand, one hundred twenty-one".