20477951 has 4 divisors (see below), whose sum is σ = 22053192. Its totient is φ = 18902712.

The previous prime is 20477929. The next prime is 20477957. The reversal of 20477951 is 15977402.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20477951 - 2¹⁸ = 20215807 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20477957) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 787601 + ... + 787626.

It is an arithmetic number, because the mean of its divisors is an integer number (5513298).

Almost surely, 2^20477951 is an apocalyptic number.

20477951 is a deficient number, since it is larger than the sum of its proper divisors (1575241).

20477951 is a wasteful number, since it uses less digits than its factorization.

20477951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1575240.

The product of its (nonzero) digits is 17640, while the sum is 35.

The square root of 20477951 is about 4525.2570092758. The cubic root of 20477951 is about 273.5870268392.

The spelling of 20477951 in words is "twenty million, four hundred seventy-seven thousand, nine hundred fifty-one".