20513547 has 16 divisors (see below), whose sum is σ = 30535680. Its totient is φ = 13610376.

The previous prime is 20513531. The next prime is 20513551. The reversal of 20513547 is 74531502.

It is a happy number.

It is not a de Polignac number, because 20513547 - 2⁴ = 20513531 is a prime.

It is a super-2 number, since 2×20513547² = 841611221042418, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 20513547.

It is not an unprimeable number, because it can be changed into a prime (20513557) 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, 4318 + ... + 7724.

It is an arithmetic number, because the mean of its divisors is an integer number (1908480).

Almost surely, 2^20513547 is an apocalyptic number.

20513547 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

20513547 is a deficient number, since it is larger than the sum of its proper divisors (10022133).

20513547 is a wasteful number, since it uses less digits than its factorization.

20513547 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3639 (or 3633 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 20513547 is about 4529.1883378813. The cubic root of 20513547 is about 273.7454568584.

The spelling of 20513547 in words is "twenty million, five hundred thirteen thousand, five hundred forty-seven".