11611551 has 16 divisors (see below), whose sum is σ = 17798400. Its totient is φ = 6595968.

The previous prime is 11611549. The next prime is 11611559. The reversal of 11611551 is 15511611.

It is a happy number.

It is not a de Polignac number, because 11611551 - 2¹ = 11611549 is a prime.

It is a super-4 number, since 4×11611551⁴ (a number of 29 digits) contains 4444 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11611559) 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, 2215 + ... + 5303.

It is an arithmetic number, because the mean of its divisors is an integer number (1112400).

Almost surely, 2^11611551 is an apocalyptic number.

11611551 is a deficient number, since it is larger than the sum of its proper divisors (6186849).

11611551 is a wasteful number, since it uses less digits than its factorization.

11611551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3278.

The product of its digits is 150, while the sum is 21.

The square root of 11611551 is about 3407.5725964387. The cubic root of 11611551 is about 226.4453522729.

The spelling of 11611551 in words is "eleven million, six hundred eleven thousand, five hundred fifty-one".