1621560294025 has 27 divisors (see below), whose sum is σ = 2339082281991. Its totient is φ = 1111896497040.

The previous prime is 1621560294019. The next prime is 1621560294031. The reversal of 1621560294025 is 5204920651261.

The square root of 1621560294025 is 1273405.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (1621560294019) and next prime (1621560294031).

It can be written as a sum of positive squares in only one way, i.e., 583761705849 + 1037798588176 = 764043^2 + 1018724^2 .

It is not a de Polignac number, because 1621560294025 - 2¹³ = 1621560285833 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 44550984 + ... + 44587366.

Almost surely, 2^{1621560294025} is an apocalyptic number.

1621560294025 is the 1273405-th square number.

1621560294025 is the 636703-rd centered octagonal number.

It is an amenable number.

1621560294025 is a deficient number, since it is larger than the sum of its proper divisors (717521987966).

1621560294025 is an frugal number, since it uses more digits than its factorization.

1621560294025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72790 (or 36395 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 43.

The spelling of 1621560294025 in words is "one trillion, six hundred twenty-one billion, five hundred sixty million, two hundred ninety-four thousand, twenty-five".