1221501025 has 12 divisors (see below), whose sum is σ = 1566891900. Its totient is φ = 943503680.

The previous prime is 1221501023. The next prime is 1221501067. The reversal of 1221501025 is 5201051221.

It can be written as a sum of positive squares in 6 ways, for example, as 80209936 + 1141291089 = 8956^2 + 33783^2 .

It is not a de Polignac number, because 1221501025 - 2¹ = 1221501023 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221500993 and 1221501011.

It is not an unprimeable number, because it can be changed into a prime (1221501023) 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, 841690 + ... + 843139.

It is an arithmetic number, because the mean of its divisors is an integer number (130574325).

Almost surely, 2^1221501025 is an apocalyptic number.

It is an amenable number.

1221501025 is a deficient number, since it is larger than the sum of its proper divisors (345390875).

1221501025 is a wasteful number, since it uses less digits than its factorization.

1221501025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1684868 (or 1684863 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 1221501025 is about 34949.9788984200. The cubic root of 1221501025 is about 1068.9677718173.

Adding to 1221501025 its reverse (5201051221), we get a palindrome (6422552246).

The spelling of 1221501025 in words is "one billion, two hundred twenty-one million, five hundred one thousand, twenty-five".