18201261 has 16 divisors (see below), whose sum is σ = 26260416. Its totient is φ = 11147136.

The previous prime is 18201229. The next prime is 18201277. The reversal of 18201261 is 16210281.

18201261 = T₂₇₃ + T₂₇₄ + ... + T₅₀₅.

It is not a de Polignac number, because 18201261 - 2⁵ = 18201229 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18201661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8086 + ... + 10088.

It is an arithmetic number, because the mean of its divisors is an integer number (1641276).

Almost surely, 2^18201261 is an apocalyptic number.

It is an amenable number.

18201261 is a deficient number, since it is larger than the sum of its proper divisors (8059155).

18201261 is a wasteful number, since it uses less digits than its factorization.

18201261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2252.

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 18201261 is about 4266.2935904600. The cubic root of 18201261 is about 263.0472862877.

It can be divided in two parts, 1820 and 1261, that added together give a triangular number (3081 = T₇₈).

The spelling of 18201261 in words is "eighteen million, two hundred one thousand, two hundred sixty-one".