1621441261 has 6 divisors (see below), whose sum is σ = 1782245486. Its totient is φ = 1474037400.

The previous prime is 1621441253. The next prime is 1621441303.

1621441261 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 1612022500 + 9418761 = 40150^2 + 3069^2 .

It is not a de Polignac number, because 1621441261 - 2³ = 1621441253 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 (1621441201) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6700050 + ... + 6700291.

Almost surely, 2^1621441261 is an apocalyptic number.

1621441261 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1621441261 is a deficient number, since it is larger than the sum of its proper divisors (160804225).

1621441261 is a wasteful number, since it uses less digits than its factorization.

1621441261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13400363 (or 13400352 counting only the distinct ones).

The product of its digits is 2304, while the sum is 28.

The square root of 1621441261 is about 40267.1238232879. The cubic root of 1621441261 is about 1174.8084820795.

It can be divided in two parts, 16214 and 41261, that added together give a palindrome (57475).

The spelling of 1621441261 in words is "one billion, six hundred twenty-one million, four hundred forty-one thousand, two hundred sixty-one".